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Since multi patterning with spacer was introduced in NAND flash memory1, multi patterning with spacer has been a promising solution to overcome the resolution limit. However, the increase in process cost of multi patterning with spacer must be a serious burden to device manufacturers as half pitch of patterns gets smaller.2, 3 Even though Nano Imprint Lithography (NIL) has been considered as one of strong candidates to avoid cost issue of multi patterning with spacer, there are still negative viewpoints; template damage induced from particles between template and wafer, overlay degradation induced from shear force between template and wafer, and throughput loss induced from dispensing and spreading resist droplet. Jet and Flash Imprint Lithography (J-FIL4, 5, 6) has contributed to throughput improvement, but still has these above problems. J-FIL consists of 5 steps; dispense of resist droplets on wafer, imprinting template on wafer, filling the gap between template and wafer with resist, UV curing, and separation of template from wafer. If dispensing resist droplets by inkjet is replaced with coating resist at spin coater, additional progress in NIL can be achieved. Template damage from particle can be suppressed by thick resist which is spin-coated at spin coater and covers most of particles on wafer, shear force between template and wafer can be minimized with thick resist, and finally additional throughput enhancement can be achieved by skipping dispense of resist droplets on wafer. On the other hand, spin-coat-based NIL has side effect such as pattern collapse which comes from high separation energy of resist. It is expected that pattern collapse can be improved by the development of resist with low separation energy.

Modified antireflective thin films for optical crystals are developed by sol gel chemistry. Hexamethyldisilazane is added to silica sol to prepare modified sol by the Stober method. The particle size distribution of the modified sol is found to have good uniformity, with an average particle diameter of about 42.14 nm. This sol can be used to prepare antireflective films with low refractive index of about 1.2. Homogeneous double layered films of antireflective and moisture resistant properties are demonstrated to coat small square sized KH 2 PO 4 /KD 2 PO 4 crystals through a combination of dip and spin coating. The modified antireflective films display residual reflectivity close to zero, and laser induced damage threshold of 10.9 J/cm 2 (pulse wavelength: 355nm, pulse width: 3ns) measured by raster scan method.

In this work, an improvement in light extraction efficiency from MDMO-PPV based OLEDs by using colloidal crystals is demonstrated. The optimal SiO2 sphere diameter for the colloidal crystal was calculated by the Plane Wave Expansion Method (PWEM), taking into account the dispersion relation of the system formed by a face-centered cubic colloidal crystal (FCC) infiltrated within the luminescent polymer MDMO-PPV. The fabrication method of such a polymer layer with a photonic crystal beneath by spin coating was proved and patented. Therefore, devices with the structure ITO/PEDOT/MDMO-PPV+SiO2 colloidal crystal/Ag were elaborated. Compared with standard OLEDs containing a single MDMO-PPV luminescent layer, the external quantum efficiency of devices modified with a colloidal crystal matrix within the MDMO-PPV layer shows a significant increment, as evaluated from the optical power as a function of applied bias for both kinds of devices.

Fabrication and characterization slab waveguide based polymethyl methacrylate (PMMA) has been carried out. Slab waveguide fabrication done by the spin coating method. Slab waveguide fabrication process carried out by the rotational speed of 1000, 2000, and 3000 rpm respectively played for 10 seconds. Then the slab waveguides heated using a hot plate. Heating process starting from room temperature then increased 5°C to 70°C with a 5 minute warm-up time interval. From the results of characterization fabricated slab waveguides to determine the film thickness is made. Then made observations on the waveguide by passing the light beam He-Ne laser on the thin layer through a single mode optical fiber. From the results of characterization is known that the fabrication of a slab waveguide with a layer thickness of 166 μm. From this research it is known that polymethyl methacrylate (PMMA) can be used as a waveguide with a spin coating method.

The straight waveguide SnO2 nanoparticles was fabricated with isopropanol solvent. SnO2 nanoparticles straight films were deposited on acrylic substrate at 100 °C using sol-gel method and cover PMMA were deposited by spin coating method. The wide of the film obtained 0.35 mm. The channel of straight used graphir acrylic with different lengths: 10 mm, 15 mm and 20 mm. This research was intended to determine loss of the films and examination absorbance and transmittance. From the research results of absorbance and transmittance using UV-Vis known that highest absorption is 295 nm and average transmittance is 84.074%. The loss of the straight waveguide with different lengths: 10 mm: 2.784 %, 15 mm: 7.927 % and 20 mm: 18.352 %.

Many types of yttria-stabilized zirconia (YSZ) based gas sensors have been explored extensively in recent years. Great attention have been directed to mixed-potential-type gas sensors. It is due to growing concerns with environmental issues. Not without a significance is the fact of very attractive performance of this type of sensor allowing to detect low concentration of pollutant gases. In this paper two types of YSZ based mixed-potential planar sensors were investigated, with platinum electrode painted using commercial paste and with spin coated platinum layer. Both types had second electrode in the form of porous gold. Measurements were performed at 400 °C in synthetic air and different concentrations of SO2. Gas flow was set to 100 cm3min-1 and the concentration of 50 ppm SO2 was tested. During this measurements the sensor was sintered in-situ at increasing temperatures. Sensor with 100 nm spin-coated platinum layer sintered at 700 °C was shown to exhibit two times smaller response than sensor with 5 μm porous electrode, while consisting of over 20 times smaller amount of Pt. The influence of sintering temperature on electrical conductivity of platinum films was also examined. Moreover, the platinum microstructure was investigated using SEM microscopy.

In this work, we make reduced graphene oxide (rGO) solution via chemical way and use it to fabricate Field-effect transistor (FET) channel by spin coating for investigating the performance of grapheme-based devices. An inductively coupled plasma (ICP) with very low plasma density is applied to etch the surface of rGO. It has been confirmed that residues and contaminations can be removed through etching and proper etching parameters can lead to better electrical properties more like the pristine graphene without creating defects. Considering the application of graphene added to silicon-based electronic devices, such a cleaning method can be used due to its advantages of being a low-temperature, large-area, high-throughput, and Si-compatible process.

Oleylamine is used as a passivating layer instead of commercial high temperature SiNx. Oleylamine coating applied on the n-type emitter side with p-type base polycrystalline silicon solar cells at room temperature using a simple spin coating method. It has been observed that there is 16% increase in efficiency after Oleylamine coating. Further, the solar cell was subjected to standard characterization namely current-voltage measurement for electrical parameters and Fourier transform infrared spectroscopy to understand the interaction of emitter surface and passivating Oleylamine. However, the passivation layer is not stable due to the reaction between Oleylamine and ambient air content such as humidity and carbon dioxide. This degradation can be prevented with suitable overcoating.

We investigate the effect of the incorporation of CdSe quantum dots (QD) in the standard ITO/TPD/Alq3/Al organic light emitting diodes (OLED's). The OLED's structures have been prepared in a double glove box coupled to a vacuum chamber containing both low and high temperature evaporators. For the standard (undoped) OLED's, the hole transport layer (HTL) consisting of 50nm of TPD is deposited by spin coating (8000rpm during 60 sec) and the 40nm of Alq3 were deposited at 2A/sec (organic crucible Radak-I). 150nm of Al were finally evaporated at 5A/s. For the CdSe-doped OLED's, the procedure was the same expect that the QD's were mixed with TPD in toluene before spin coating. During the thermal processing if the film, the QD's are expected to segregate to the surface, and then will be located at the TPD/Alq3 interface. The various layers were imaged by Atomic Force Microscopy (AFM) at each phase of the structure deposition, and we could indeed visualize the segregated QD's above the TPD film. AFM was systematically used to monitor the homogeneity and the thickness of the various films. The impedance of the non-encapsulated films structures were measured in air in the 40-40MHz frequency range, with bias at 0V (non-emitting), 2V (low emission) and 8V (strong emission). The corresponding dielectric spectra were analyzed with the standard Havriliak-Negami (HV) formula, where the conductive term has been subtracted from the data in case of light emission. We have measured a relaxation ranging from 100kHZ for the unbiased structure to 1MHz for 8V (strong emission). Apart from this expected relaxation, we found a second relaxation mechanism around 10 MHz. The origin of this second peak will be discussed. To monitor the optical emission of the OLED's, we have built a specific bench which allows for the quantitative measurement of the emission spectra and the dynamics behavior of the OLED's (raising and falling time). We found that the incorporation of the QD's unfortunately results in the decrease of the light emission but with a favorable modification of the light spectrum (around 700nm).

In this study, Mg-doped CdS nanostructure was deposited onto anodic aluminum oxide (AAO) membrane substrate using sol-gel spin coating method. The AAO membrane was prepared by a two-step anodization process combined with pore widening process. The morphology, chemical composition, and structure of the spin- coated CdS nanostructure have been studied. The morphology of the fabricated AAO membrane and the deposited Mg-doped CdS nanostructure was investigated using scanning electron microscopy (SEM). The SEM of AAO illustrates a typical hexagonal and smooth nanoporous alumina membrane with interpore distance of ~ 100 nm, the pore diameter of ~ 60 nm. SEM of Mgdoped CdS shows porous nanostructured film of CdS nanoparticles. This film well adherents and covers the AAO substrate. The energy dispersive X-ray (EDX) pattern exhibits the signals of Al, O from AAO membrane and Mg, Cd, and S from the deposited CdS. This indicates the high purity of the fabricated membrane and the deposited Mg-doped CdS nanostructure. Using X-ray diffraction (XRD) pattern, Scherrer equation was used to calculate the average crystallite size. Additionally, the texture coefficients and density of dislocations were calculated. The fabricated CdS/AAO was applied to detect glucose of different concentrations. The proposed method has some advantages such as simple technology, low cost of processing, and high throughput. All of these factors facilitate the use of the prepared films in sensing applications.

Titanium dioxide thin film plays an important role in thin film solar cells, and has promising future in everyday applications including air cleaning and self-cleaning glass. With the concepts of flexible solar cells and wearable devices being more and more popular, there is increasing interest to coat titanium dioxide thin films on flexible substrates, such as aluminum foils. Many methods have been used to fabricate titanium dioxide thin films, such as dip-coating, spin coating, aerosol spray, plasma-assisted coating, electrospraying, and so on. Among them, electrospraying is especially suitable for thin film deposition on flexible substrates. This work reports fabrication of dense and uniform titanium dioxide thin films on glass as well as flexible aluminum foil using multi-jet electrospraying technique.

An optical fibre long period grating (LPG) coated with an inorganic molecularly imprinted thin film based on TiO 2 was used to measure in real time the photodecomposition of an organic target compound. The TiO 2 film was deposited onto the LPG using the aqueous liquid phase deposition method and its photo-catalytic properties were employed to decompose a porphyrin. The principle of operation is based on the measurements of the refractive index (RI) change of the TiO 2 thin film at the binding and removal of the imprinted organic compound. Keywords: long period grating (LPG), molecularly imprinte d polymers (MIPs), selective photodecomposition. 1. INTRODUCTION Optical techniques are considered widely to be powerful tools for the development of chemical and biological sensors, covering a wide range of applications [1]. Sensing techniques based upon the use of optical fibre long period grating (LPG) devices to probe the opti cal characteristics of nanomaterials that exhi bit changes in their optical properties upon exposure to targeted chemical species are particularly attractive, due to their potential high sensitivity, the ability to multiplex arrays of sensors, and the prospect for remote sensing [2]. Molecularly imprinted materials provide a universal platform for the creation of artificial receptors that can be well controlled and tailored to achieve precise molecular recognition [3]. The technique is very versatile as any compound with functional groups can in theory be imprinted in different porogens (either water or organics). The basic concept of molecular imprinting is based on the creation of imprints of the template (i.e. chemical molecules or biological species that need to be detected – the analyte) into a matrix. The matrix is most often polymeric, with molecular imprinting achieved by incorporation of the template during the polymerization step, which is subsequently removed to leave behind a cavity specific for the template material, as illustrated in figure 1. Inorganic and hybrid inorganic-organic molecularly imprinted materials have advantages over those prepared from organic materials. Such materials are highly stable and reproducible, which is esp ecially important in real world sensing applications. Inorganic MI has been achi eved successfully using various metal alkoxi des, most often using silica to form the inorganic matrix via a sol-gel process that incorporates the template molecule [3]. Other methods that have been employed for the preparation of the thin imprinted films include organically modi fied sol-gels [4], gas-phase surface sol-gel deposition [3], liquid phase deposition [5 ] and spin coating [6]. One of the disadvantages of using metal alkoxides is the need to use organic solvent which limits the ability to use water soluble templates in the MI technique. In this work we propose a different approach for the fabrication of molecularly imprinted thin inorganic films using water soluble compounds. The approach involves the deposition onto the LPG of the TiO

We report an easy way to tune the optical refractive index and viscosity of an epoxy acrylate-based host-guest system which can be used for the fabrication of optical waveguides. This allows fast and precise modification of the material system for different replication methods like hot embossing, inkjet printing or spin coating. To modify the refractive index n, an electron-rich organic dopant such as phenanthrene is added to a commercially available reactive polymer based resin. Moreover, changes in viscosity can be achieved by using a comonomer with suitable properties like benzyl methacrylate (BMA). We used a commercially available UV-curable epoxy acrylate based polymer matrix to investigate both the influence of phenanthrene and of benzyl methacrylate. First, mixtures of the pure polymer and benzyl methacrylate with a ratio of 30, 50, and 80 wt% benzyl methacrylate were produced. Second, phenanthrene was added with 5 and 10 wt%, respectively. All components were mixed and then polymerized by UV-irradiation and with a thermal postcure. The viscosity of the mixtures decreased at 20°C linearly from 1.5 Pa·s (30 wt%) to 8 mPa·s (80 wt%), whereas the refractive index decreased at the same time by a small amount from 1.570 to 1.568 (@589 nm, 20 °C). By adding phenanthrene refractive index increased to a maximum of n = 1.586 (50 wt% BMA, 10 wt% phenanthrene). Abbe numbers for the compositions without phenanthrene ranged from 35 to 38.

Regioregular poly(3-hexylthiophene) (rr-P3HT) is suitable for electronic noses and the detection of gaseous biomarkers of human diseases to clinical diagnosis. Nevertheless, thin-film properties such as crystallinity and thickness play a major role in overall device performance. Thin-films were obtained from spin coating of 2–20 mg/mL solutions in chloroform, toluene, chlorobenzene and dichlorobenzene to form a thickness from 20 to 160 nm as measured by atomic force microscopy (AFM). Absorbance spectrum fitted by the sum of three Gaussian curves defined the following parameters, which correlate with the film's electronic structure/morphology: (i) the abscissa at the center of the Gaussian from the highest wavelength, which responds for the P3HT band gap, and (ii) the ratio between the area under the Gaussian centered at the lowest wavelength over the one at the highest wavelength, which corresponds to the amount of amorphous and crystalline phase, respectively. Isosbestic point was determined by thermal annealing temperature variation, while keeping the thickness constant. It was observed that absorbance spectrum shape and, consequently, thin-film morphology depend not only on the concentration of the solution, but also on solvent. Finally, the isosbestic point determined at (470 ± 3) nm provides a linear relationship between absorbance and thickness with y-axis intercept approaching zero. The absorbance spectrum and isosbestic point of P3HT provides a non-destructive, faster and reliable way to estimate thin-film properties as thickness and crystallinity without recurring to AFM and X-ray diffraction (XRD) measurements.

We obtained Gallium-doped and Aluminum-doped Zinc Oxide nanocrystals by non aqueous colloidal heat-up synthesis. These nanocrystals are transparent in the visible range but exhibit localized surface plasmon resonances (LSPRs) in the near IR range, tunable and shiftable with dopant concentration (up to 20% mol nominal). GZO and AZO inks can be deposited by spin coating, dip coating or spray coating on glass or silicon, leading to uniform and high optical quality thin films. To enhance absorbtion in the infrared region, samples can be annealed in inert or reductant atmosphere (N2/Argon or H2 in Argon) resulting in plasmon intensity enhancement due to oxygen vacancies and conduction band electrons density increment. Then IR plasmon has been exploited for gas sensing application, according to the plasmon shifting for carrier density variations, due to electrons injection or removal by the target gas/sample chemical interactions. To obtain a functional sensor at low temperature, another treatment was investigated, involving surfanctant removal by dipping deposited films in a solution of organic acid, tipically oxalic acid in acetonitrile; such process could pave the way to obtain similar sensors deposited on plastics. Finally, GZO and AZO thin films proved sensibility to H2 and NOx, and in particular circumstances also to CO, from room temperature to 200°C. Sensibility behavior for different dopant concentration and temperture was investigated both in IR plasmon wavelengths (~2400 nm) and zinc oxide band gap (~370 nm). An enhancement in sensitivity to H2 is obtained by adding Pt nanoparticles, exploiting catalytic properties of Platinum for hydrogen splitting.

We report the realization and characterization of porous nanostructures where a periodic refractive index modulation is achieved by stacking layers with different nano-architectures. One multilayer photonic crystal has been fabricated starting from colloidal dispersion of silicon dioxide and zirconium dioxide using spin coating technique. Improved efficiency of Bragg reflectivity (up to 85%) has been obtained by a new bottom-up fabrication technique of photonic hierarchical nanostructures based on self-assembly from the gas-phase at low temperature whit a very thin (≈ 1 μm) photonic crystal devices. Due to the high porosity, these systems can be infiltrated with nematic liquid crystals leading to tuning of the Bragg reflection band by applying low voltages to the structure.

Periodic nanostructure arrays have been ubiquitously exploited lately due to their properties and prospective applications in production of templates for self-induced and gold (Au)-catalysed nanowires (NWs), because this approach is relatively cheap, time-efficient and do not require electron beam lithography. The technique consists creating nanoholes in SiO 2 to expose the silicon Si (111) beneath where self-induced NWs can nucleate, while nanodots deposited onto the Si (111) surface serve as catalyst seeds. For Au-catalysed NWs, a monolayer of self-assembled polystyrene nanospheres (PNS 300nm) was created on a 2 inch Si wafer by spin coating and later etched for a short time before a very thin Au-catalyst layer was deposited. In turn, for self-induced, PNS monolayer was created onto a SiO 2 -Si substrate. A longer etch was required to reduce PNS diameter significantly to leave relatively larger spacing where chromium is blanket deposited. PNS were lifted off by sonicating the samples in toluene produce the periodic arrays of nanodots and nanoholes, respectively. The underlying SiO 2 was etched further through the nanoholes to uncover the Si below. 200 nm holes and 30-70 nm dots were demonstrated through the bespoke methods. The patterned substrates served as master templates, subsequently copied using polydimethylsiloxane (PDMS) to produce a flexible stamp for nanoimprint lithography. A bilayer resist lift off process was developed to print the replicated nanodots or nanoholes on large-area substrates onto which III-V NWs can be grown.

The direct optical monitoring of electron exchange on single plasmonic nanoparticles, involved in chemical reactions with gas molecules, is one of the main challenges in the heterogeneous catalysis and gas sensing fields. Catalysts are substances that speed up reactions by providing an alternative pathway with lower activation energy than that required for the uncatalysed reaction. A lot of research, both fundamental and applied, has been carried out to investigate how catalysts work and to increase their efficiency. The present work shows how the use of Dark Field Microscopy (DFM) coupled with surface plasmon spectroscopy, enables the direct observation of the kinetics of H2 gas interaction with single gold nanorods (NR) coupled with Pt nanoparticles (NPs) and/or with metal oxide matrices. The plasmonic particles, gold NRs, act as optical probes, and enable the monitoring of the electron exchange through the measurement of their surface plasmon resonance (SPR) band shift. To improve the redox reaction kinetics, the Au NRs have been coupled with Pt NPs and embedded also into a TiO2 or ZnO low scattering matrix. The Au NRs, the Pt, TiO2 and ZnO NPs have been synthetized by colloid chemistry. Several samples made of bare Au NRs, or Au NRs coupled with only Pt NPs or with Pt and TiO2 NPs or with Pt and TiO2 have been deposited by spin coating on silica substrates. The longitudinal Au SPR band shift has been monitored by DFM looking at the variation of the scattering spectrum of a single Au NRs in the presence of H2. Time-resolved measurements have been also conducted at fixed wavelength in order to monitor the kinetics of the H2 reaction. With such measurements it was possible to elucidate the importance of the adsorbed oxygen and the TiO2 matrix on the H2 reaction with the Pt NPs.

Nanometer scale iron particles have a variety of technological applications. They are vastly utilized in optical and microwave devices. Thin films with varying compositions of iron (III) nitrate and ethylene glycol were deposited on glass substrate using a spin coating technique. The thicknesses of the films were controlled by the spin rate. Precursor films on the substrate were then annealed to different temperatures ranging from 200°C to 600°C for 1-3 hours in air. The microstructures of iron particles in films prepared under different conditions were investigated using X-ray Absorption spectroscopy and Mossbauer spectroscopy. The main absorption edge peak position and pre-edge energy position were identical in samples with different numbers of layers, but prepared under similar conditions. This indicates that there was no change in the charge state of the iron regardless of the number of layers. However the intensity of the pre-edge feature decreases as the number of layers increases, which shows a decrease of Fe-O compounds as the number of layers increases. Mossbauer spectrum of these iron particles contains only quadrupole doublets. The absence of six-linespectrum confirms the nano-size nature of the particles.

Transmissive diffractive membrane optic can be used in space optical telescope to reduce the size and mass of imaging system. Based on the international research results about transmissive diffractive membrane, a 4-level diffractive substrate with 100mm apertures was designed and transmissive diffractive membrane was fabricated by spin coating. High-precision support structure for diffractive membrane with surface precision 0.12λ RMS (λ=632.8nm) was introduced, and that can meet the diffractive imaging requirements. Diffraction efficiency of the diffractive membrane supported by support structure was tested, and the test results showed that diffraction efficiency was >50%. The step figure test results illustrated the etched deep precision was less the 10nm. The imaging wavefront test result demonstrated a wavefront error of about 38 nm RMS. The transmissive diffractive membrane optic can be very useful for large aperture imaging system to realize low mass and low cost.

RTI has developed a photodiode technology based on solution-processed PbS colloidal quantum dots (CQD). These devices are capable of providing low-cost, high performance detection across the Vis-SWIR spectral range. At the core of this technology is a heterojunction diode structure fabricated using techniques well suited to wafer-scale fabrication, such as spin coating and thermal evaporation. This enables RTI’s CQD diodes to be processed at room temperature directly on top of read-out integrated circuits (ROIC), without the need for the hybridization step required by traditional SWIR detectors. Additionally, the CQD diodes can be fabricated on ROICs designed for other detector material systems, effectively allowing rapid prototype demonstrations of CQD focal plane arrays at low cost and on a wide range of pixel pitches and array sizes.

We report a fabricating method for ion-conducting carbon electrodes on top of industrially produced PVDF membrane by spin-coating. Spin-coating is desirable due to its potential application in large-scale actuator manufacturing and its possibility to produce very thin electrodes. The industrial grade membrane was chosen in order to investigate more accurately the results of spin-coating without considering the deviations present in a hand-made membrane. Spin-coating and surface resistivity measurements via four-point probe were described in further detail. The production process of electrode suspension and suspension dispensing were developed and fine-tuned. The spin coater was programmed to obtain electrodes with uniform electrical properties. The arrangement of the spin coater was slightly altered to remove swelling and bubble formation effects concurrent with usage of the porous membrane. Electrodes produced with the developed method were measured and analyzed. Thickness of the film was measured with micrometer screw gauge and four-point probe was used to measure sheet resistivity, in addition film was studied under scanning electron microscope. In best cases the coefficient of variation for sheet conductivity was 6.2%. For all electrode sheet conductivities the median coefficient of variation was 7%. The thickness of the electrodes varied from 6 to 23 μm. As a proof of concept for the developed method a working actuator with spin-coated electrodes was produced.

MgAl 2 O 4 and ZnAl 2 O 4 both have the spinel structure and similar lattice constants, but the bandgap of MgAl 2 O 4 is about double that of ZnAl 2 O 4 , making it interesting to consider the mixed spinel (Mg x Zn 1-x )Al 2 O 4 as a possible host for luminescent ions. Prior to preparing thin films, the Mg:Zn ratio and Tb concentration were optimized for green luminescence from the 5 D 4 - 7 F 5 transition of Tb 3+ ions using nanocrystalline samples prepared by combustion synthesis. Thin films with x = 0.75 and 0.5 mol% Tb were spin-coated on Si(100) substrates using a solution of the nitrates of Mg, Zn, Al and Tb in ethanol, with ethylene glycol as complexing agent. Samples about 200 nm thick were obtained by sequentially depositing 10 layers at 3000 rpm for 30 s. Samples were annealed for 1 h in air before measuring their luminescence properties. For the sample annealed at 600 °C, x-ray diffraction showed the thin film had a strong (111) preferential orientation. Atomic force microscopy revealed a root means square roughness of 1 nm and Auger electron spectroscopy depth profiles showed a uniform layer with a sharp interface at the Si substrate. With an increase in annealing temperature up to 1000 °C, the luminescence increased while the surface became slightly rougher and the layer-substrate interface more interdiffused. Annealing the samples at 1200 °C resulted in diffusion of Si through the layer and the formation of an additional phase. While the green Tb emission was slightly reduced, blue emission from the 5 D 3 level of Tb 3+ was greatly enhanced in these samples.

Fabrication of optical tissue phantom (OTP) simulating whole skin structure has been regarded as laborious and time consuming work. This study fabricated multilayer OTP optically and structurally simulating epidermis-dermis structure including blood vessel. Spin coating method was used to produce thin layer mimicking epidermal layer, then optimized for reference epoxy and silicone matrix. Adequacy of both materials in phantom fabrication was considered by comparison the fabrication results. In addition similarities between OTP and biological tissue in optical property and thickness was measured to evaluate this fabrication process.

Pi-conjugated polymer light emitting devices have the potential to be the next generation of solid state lighting. In order to achieve this goal, a low cost, efficient and large area production process is essential. Polymer based light emitting devices are generally deposited using techniques based on solution processing e.g.: spin coating, ink jet printing. These techniques are not well suited for cost-effective, high throughput, large area mass production of these organic devices. Ultrasonic spray deposition however, is a deposition technique th at is fast, efficient and roll to roll compatible which can be easily scaled up for the production of large area polymer light emitting devices (PLEDs). This deposition technique has already successfully been employed to produce organic photovoltaic devices (OPV) 1 . Recently the electron blocking layer PEDOT:PSS 2 and metal top contact 3 have been successfully spray coated as part of the organic photovoltaic device stack. In this study, the effects of ultrasonic spray depos ition of polymer light emitting devices are investigated. For the first time – to our knowledge -, spray coating of the active la yer in PLED is demonstrated. Different solvents are tested to achieve the best possible spray-able dispersion. The active layer morphology is characterized and optimized to produce uniform films with optimal thickness. Furthermore these ultrasonic spray coated films are incorporated in the polymer light emitting device stack to investigate the device characteristics and efficiency. Our results show that after careful optimization of the active layer, ultrasonic spray coating is prime candidate as deposition technique for mass production of PLEDs. Keywords: Organic light emitting diodes, ultrasonic spray coating, solution processing.

Recent studies of poly(3-hexylthiophene) solutions demonstrate that „sample history” (solution preparation, storage conditions) affects the aggregation process(es) and, consequently, electrical properties. In this paper, we demonstrate the evolution of UV-Vis spectra and the formation of additional red-shifted peaks which visualize the aggregation of p3ht chains. We report comparative study of p3ht based organic field effect transistors fabricated by spin coating using fresh and aged (for 6 months) chloroform solutions with anisole addition. Three order of magnitude improvement in the oFET charge carrier mobility is exhibited. These results provide new insight into p3ht crystallization process(es) and nanofiber-based oFETs.

The Materials and Manufacturing Directorate of the Air Force Research Laboratory (AFRL) began studies of deoxyribonuclaic acid (DNA) as a polymer material in 2001 due to the availability of multi-gram quantities of 98% pure DNA extracted from Japanese salmon waste products. The research studies that followed explored the electrical, optical and electrooptical characteristics of thin films of DNA combined with the surfactant hexacytltrimethylammonium chloride making the resulting DNA-CTMA complex soluble in most polar solvents and insoluble in water. The films were produced mainly by spin coating although other techniques were also used. The focus was to measure the fundamental properties, such as volume electrical resistivity, dielectric constant, refractive index and thermal conductivity, and to explore various applications using test device configurations such as an optical modulator, OFET, OLED and energy storage capacitor fabricated using DNA-CTMA. The initial high molecular weight of 2,000 to >8,000 kDa was reduced by high power ultrasonic treatment, which provided molecular weight materials from 1,000 down to ~200 kDa. These lower molecular weight materials revealed changes in some properties of the DNA-CTMA material. This paper brings together the results of these studies to show the potential of DNA as a polymer material.

We fabricated the inverted polymer solar cells (PSCs) with a structure of ITO/ZnO/PTB7:PC71BM/MoO3/Ag, and investigate the influence of spin coating on the device performance in this article. Through modifying the spin coating parameters, the high PSC performance could be obtained with VOC=0.769 (V), JSC=11.6 (mA/cm2), FF=58.8 % and PCE=5.26 %, respectively. The improvement of device performance was attributed to the enhanced absorption of active layer in the wavelength from 550 nm to 700 nm and the increased phase separation of PTB7:PC71BM.

Quartz Crystal Microbalance (QCM) coated with polyetherimide (PEI) by spin coating method was applied for carbon dioxide (CO 2 ) gas detection at room temperature in this study. The experiments were performed in dry and humid air atmospheres, and the results revealed that the prepared CO2 sensor in moisture circumstance exhibited a larger sensing response than that at dry condition. An enhanced sensing response took place for CO 2 detection with the existence of water molecules. The effect of different humidity on QCM sensor performances was investigated as well in this paper. A curve, which displayed a proportional relationship between sensing response and water vapor concentration, was obtained. Moreover, the relevant sensing mechanisms were investigated.

Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer, which indicates four different crystalline forms. In this paper, the preparation of nanoscale PVDF thin film was introduced in detail. Initially PVDF was dissolved in the N,N-dimethyl Formamide and acetone mixed solution (volume ratio 1:1). The PVDF films were prepared by spin coating method with different solution concentration, then were characterized by SEM, XRD and FTIR after annealed at different annealing temperatures (60 centigrade to 120 centigrade). Due to the formation of polarized β crystal phase in the annealing process, the pyroelectric coefficient p would be affected by different annealing temperatures. The thermal poling technique of PVDF was also shown in this paper. We investigated the polarization behavior of PVDF when they were subjected to different poling electric fields (from 50 V/μm to 80 V/μm) and poling temperatures (from 90 centigrade to 120 centigrade). For a long enough poling time, the polarization is only related to poling electric filed, while poling temperature affects the poling rate merely. Under the condition of PVDF thin film beforet breakdown, the strongger the poling electric filed intensity, the higher the pyroelectric coefficient is. The pyroelectric coefficient of fibricated PVDF film is 9.0×10 -10 C/cm 2 K after 80v/μm electric field intensity polarization from experiment result.

An alternative fabrication method for dye-doped DNA-surfactant complex films was developed and amplified spontaneous emission (ASE) and lasing under low energy optical pumping were demonstrated. In this new preparation technique, thin DNA-cethyltrimethylammonium (CTMA) complex films made by a spin coating method were stained with a hemicyanine dye by soaking them in acetone solution of the dye for one day. Molar ratio of the dye to DNA base pair for the final products was estimated to be 0.2, the value was much higher than those achieved via usual mixing method. ASE threshold value under pumping of a pulsed frequency-doubled YAG laser was about 0.3 mJ/cm 2 . Laser emission was also attained under the excitation with two interfering beams forming a dynamic grating of gain coefficient. Durability test indicated that 70% of their initial performance was maintained after 1 hour of continuous pumping. The technique was applied to water soluble dyes because the DNA complex was insoluble to water as well as acetone. We employed anionic Eosin Y dye, succeeding in sample formation and ASE emission. Different types of surfactants were also complexed with DNA, showing variation of emission peak wavelength. These results give a clue about the structure of the complex or interaction modes between DNA and surfactants, strongly suggesting that dye molecules are not intercalated into nor bound to DNA double strand directly, but are incorporated in the complex system via ion-exchange process or aggreg ating with cationic surfactants. Keywords: DNA complex, CTMA, dye laser, hemicyanine, eosin Y, thin film

We report on the power conversion efficiency (PCE) enhancement for organic solar cells (OSCs) based on several approaches. A standard cell composed of an indium tin oxide (ITO) anode, P3HT/ PCBM active layer, PEDOT:PSS hole transport layer and an aluminum cathode is used as a reference. We investigate the effects of the following three modifications. We first incorporate CdSe quantum dots (QDs) in the photo-optically active P3HT/PCBM blend in order to enhance the optical absorption. In opposite to other studies, QDs are not used here to replace the donor material (PCBM), and we always measured an enhanced PCE compared to the standard cell with a QDs:P3HTPCBM volume ratio up to 1:5. As a second modification, NaYF 4 :Yb,Er up conversion (UC) microcrystals are incorporated into a TiO 2-x sol-gel to form an additional layer used to convert IR photons to blue and green photons. Again, OSCs with UC layer showed an improved PCE compared to the reference cell. The PCE enhancement is both attributed to the IR light absorption and to a better electron transport between the active layer and the cathode due to the electron transport layer capabilities of TiO 2-x . Finally, MoO 3 layer is used to replace the PEDOT:PSS layer as hole transport layer (HTL). This layer is deposed either by thermal evaporation or by spin coating from a sol-gel solution. We found evaporation better in terms of thickness control and reproducibility. It has been demonstrated that the PEDOT:PSS HTL can be replaced by MoO 3 , and the thickness of this MoO 3 layer strongly affects the PCE of the cell. The maximum PCE was obtained with a thickness of 40nm, and again is better that the reference cell.

Chemically synthesized gold-silica nanorods were incorporated into the active layer of solution processed organic photovoltaic devices to enhance the absorption of light by the surface plasmon resonance effect in metallic nanoparticles. Solution processed polymer:fullerene and small molecule:fullerene bulk heterojunction devices were studied. The polymer donors include regioregular poly(3-hexylthiophene) (P3HT) and low bandgap poly[2,6-(4,4-bis-(2-ethylhexyl)- 4N-cyclopenta[2,1-b:3,4-b’] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT). For the small molecule device, 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']-dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5-yl) benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2) was used as the donor. The donors are blended with either [6,6]-phenyl- C61-butyric acid methyl ester (PC60BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM). The gold-silica nanorods have an aspect ratio (length/diameter) of 3.2 and 2.3 and a shell thickness of ~10 nm. Prior to spin coating, the nanorods were added directly to the donor:acceptor blend solution in either chlorobenzene or dichlorobenzene at different weight percentage of the total donor:acceptor weight. The transverse and longitudinal surface plasmon resonance peaks of the gold-slica nanorods overlap with the absorption spectra of all three donor:acceptor blends to differing degrees. As a result, the power conversion efficiency of optimized plasmonic P3HT:PC60BM and PCPDTBT:PC70BM devices with conventional structure under AM1.5G illumination at 100mW/cm2 were increased by 9.3% (to 3.42%) and 20.8% (to 4.11%) respectively relative to the control device without nanorods. For the p-DTS(FBTTh2)2:PC70BM device, the relative improvement as compared to the control device was 24.2% (to 8.01%). Published version

We have studied the photolysis of tin clusters of the type [(RSn)12O14(OH)6] X2 using extreme ultraviolet (EUV, 13.5 nm) light, and developed these clusters into novel high-resolution photoresists. A thin film of [(BuSn)12O14(OH)6][p-toluenesulfonate]2 (1) was prepared by spin coating a solution of (1) in 2-butanone onto a silicon wafer. Exposure to EUV light caused the compound (1) to be converted into a substance that was markedly less soluble in aqueous isopropanol. To optimize the EUV lithographic performance of resists using tin-oxo clusters, and to gain insight into the mechanism of their photochemical reactions, we prepared several compounds based on [(RSn)12O14(OH)6] X2. The sensitivity of tin-oxide films to EUV light were studied as a function of variations in the structure of the counter-anions (X, primarily carboxylates) and organic ligands bound to tin (R). Correlations were sought between the EUV sensitivity of these complexes vs. the strength of the carbon-carboxylate bonds in the counteranions and vs. the strength of the carbon-tin bonds. No correlation was observed between the strength of the carboncarboxylate bonds in the counter-anions (X) and the EUV photosensitivity. However, the EUV sensitivity of the tinoxide films appears to be well-correlated with the strength of the carbon-tin bonds. We hypothesize this correlation indicates a mechanism of carbon-tin bond homolysis during exposure. Using these tin clusters, 18-nm lines were printed showcasing the high resolution capabilities of these materials as photoresists for EUV lithography.

Contact hole (CH) patterning by directed-self-assembly (DSA) of polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymers (BCPs) is extensively studied in this paper. Based on statistical analysis performed on 300mm wafers, a process window (PW) for CH shrink is experimentally evaluated in terms of hole open yield and critical dimension (CD) variation after DSA as a function of BCPs of different natural periods and guiding patterns of different dimensions. The PW allowed us to define the suitable BCP molecular weight with the best guiding CD ranges required to achieve a desired DSA hole CD within a specific tolerance. As example, for a DSA hole CD targeted at 19.5 nm with 10% tolerance, circular guiding patterns of 52 nm CD with 20% guiding CD latitude are needed using a 35nm-natural-period BCP. It is also shown that the CH shrink PW is dependent on guiding pattern pitch and on DSA process conditions such as the self-assembly annealing and spin coating conditions. In addition, the study highlights an interesting property of commensurability between guiding pattern dimensions and BCP’s natural period that governs the CH patterning by DSA for both CH shrink and CH doubling configurations. This permits to predict the guiding pattern dimensions needed for CH patterning by DSA using a given BCP of known natural period.

Progress in lithographic resolution has made the adoption of extremely thin photoresist films necessary for the fabrication of ‘2× nm’ structures to prevent issues such as resist collapse during development. While there are resists with high etch durability, ultimately etch depth is limited by resist thickness. A possible solution is the use of a multilayer etch stack. For organic hardmasks a carbon-rich material is preferred as carbon possesses a high etch resistance in silicon etch plasma processes. In terms of manufacturability it is beneficial to spin coat the carbon layer instead of using chemical vapor deposition, but the presence of carbon-hydrogen bonds in typical spin on carbon leads to line wiggling during the etch. We have previously introduced a fullerene based ‘spin on carbon’ (SoC) with high etch durability and reported on material characterization. Here we show recent advances in material development and work towards commercialization. The low hydrogen level in the material allows for high resolution etching without wiggling.

The Offner-like spectrometer, one most widely used hyperspectral imaging spectrometers, offers some advantages over other spectrometers used in pushbroom imaging spectrometry: low chromatic aberrations, a compact size with low optical distortion, and large numerical aperture. The standard Offner spectrometer is made of three spherical concentric elements-- two concave mirrors and one convex grating. Convex grating is the core part of Offner type hyper-spectral imager. Considering the difficulties in fabrication of small angles convex gratings by traditional ways, we propose a new method. The ion-beam-etching holographic grating is adopted to obtain the convex blazed gratings with blazed angle of 4°--5°, whose angle can be further reduced by dipping or spinning coating with hardenable liquids. A highly reproducible blaze angle reduction to as high as a factor of 3 is achieved by controlling the spinning speed and viscosity of solution. The precise control of the blaze angles and groove profiles will be further studied focusing on the designing of rotate dip equipment and optimization of pulling speed and viscosity of solution.

Ultrasmooth polymer films are of great importance in a large body of technical application. Photoresist technology plays a very important role in MEMS, and usually is to use optical coatings to transfer the smooth surface. In order to form different value of roughness is bright and clean surface or sacrifice layer microstructure, surface topography and its effect on the microstructure is crucial. Photoresist thin film EPG533 having different thicknesses of 270nm, 500nm, and 1 μm were deposited onto well-cleaned n-type silicon substrates by spin coating and annealed in the range from 100°C to 200°C.The effects of thermal annealing and thickness variation on the crystalline quality and surface morphology of the films were investigated by white light interferometry measurements. It was found that the film quality and morphology depend on the annealing temperature. The root-mean-square roughness and waviness on the surface change, as a result of increasing film thickness.

In order to fabricate low cost and printable CuInSe 2 (CIS) thin film solar cells, a chemical process has been developed to fabricate uniform CIS films with large grain size and close stoichiometry to chalcopyrite phase. Cu(NO 3 ) 2 , InCl 3 and ethyl cellulose (EC) were adopted to form the starting solution. CIS films were prepared by spin-coating and selenization. Precursor films and CIS films were investigated by SEM, EDS and XRD. CuCl and InCl 3 crystals appeared in the precursor films. During the selenization process, CuCl first reacted with Se vapor to form Cu 2-x Se. With increasing selenization temperature, InCl 3 reacted with Cu 2-x Se to form CIS accompanying the evaporation of chlorine in the form of gas. It is revealed that the element ratio in final CIS film is determined by the raw material ratio in the starting solution and the selenization temperature.

Polymer solar cells (PSC’s) have received much attention as a promising clean and green energy technology and the power conversion efficiency have steadily increased. There are several ways to improve the device efficiency of PSC, such as changing the active layer, insertion of the electron transport layer and the anode buffer layer. Among the several anode buffer layer materials, Poly(3,4-Ethylenedioxythiophene):Poly(styrene sulfonate) (PEDOT:PSS) is widely used as anode buffer layer due to its high transparency in the visible region, high thermal stability and mechanical flexibility. However, PEDOT:PSS suffers a problem of low conductivity and limits the device application. In this report, we present the preparation of PEDOT:PSS hole transport layer through a secondary doping with flouro compounds such as hexafluoroacetone (HFA) and hexafluoroisoproponal (HIPA) with various concentrations by spin coating technique. High performance of the hole transport layer is attributed to preferential phase segregation of PEDOT:PSS with HFA and HIPA solvent mixture treatment method. The improved performance of PSC was dependent on the structure of organic solvents and the concentration of flouro compounds in PEDOT:PSS solution. Using these optimized buffer layer, conjugated polymer solar cells with a Poly9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3- benzothiadiazole-4,7-diyl-2,5 thiophenediyl] polymer:[6,6]-phenyl-C71-butyric acid methyl esters (PCDTBT:PC71BM) bulk heterojunction have been produced. A detailed analysis of the surface morphology and optical studies are presented. The obtained results show that PEDOT:PSS optimized with HFA and HIPA organic solvents can be a very promising candidate for transparent anode buffer layer in the low cost organic solar cell devices.

Synthesis of deoxyribonucleic acid (DNA) - was cetyltrimethylammonium (CTMA) - sea buckthorn extract (SBE) at different concentrations is decribed. The complexes were processed into good optical quality thin films by spin coating on different substrates such as: glass, silica and ITO covered glass substrates. SBE contains many bioactive substances that can be used in the treatment of several diseases, such as cardiovascular disease, cancer, and acute mountain sickness. The obtained thin films were characterized for their spectroscopic, fluorescent, linear and nonlinear optical properties as function of SBE concentration. The third-order nonlinear optical (NLO) properties of thin films were determined by the optical third-harmonic generation technique at 1 064.2 nm fundamental wavelength.

Derivatives of [1]benzothieno[3,2-b]benzothiophene (BTBT) are attracting much attention as a highly soluble, highmobility semiconductor material for thin-film transistor applications. These small molecules are known to organize themselves into a single crystalline structure after spin coating or drop casting. Charge transport in a single crystal material is anisotropic in nature. Hence, it is desired to control its orientation during growth or recrystallization so that the source and drain electrodes of a transistor are to be placed along a faster transport direction. We propose to generate temperature gradient in a heated liquid crystalline thin film to induce lateral recrystallization. In experiment, we tried two methods. First, an aluminum plate with two narrow ridges was inserted between a temperature-controlled stage and a square silicon substrate with a 200nm-thick SiO 2 and a spin-coated C 8 -BTBT film. We raised the temperature of the stage to 120oC and let it cool gradually. During cooling at around 105oC , the color of the sample started to change, indicating a phase change. This change proceeded from the corners of the film and in about 30 seconds, darker regions merged at the center of the substrate. Second, the sample was placed at the edge of the stage. In this case, the color change started from the protruding corner of the sample and proceeded toward the other end. Micrograph observation revealed that cracks were formed in these films and they were perpendicular to the direction of the phase change.

This paper focuses on industrial aspects of the material development of DPP-Polymers for the application in solution processed field effect transistors. It is shown that optimization of processing conditions can have a significant effect on transistor performance for a certain polymer. Although the solubility of DPP-Polymers is in general much higher than that of highly crystalline polymers like Poly-3-hexylthiophene (P3HT), transforming the polymer powder into a film is still challenging. Semiconductor film morphology and thus transistor performance strongly depends on the film formation process. Aspects of device architectures and testing conditions will also be discussed.

Periodic arrays of sub-wavelength structures have garnered significant interest for surface enhanced Raman spectroscopy (SERS) and metal enhanced fluorescence (MEF), and for anti-reflective coating properties. For SERS and MEF, coupling metal nanoparticles with nanometer scale spacing can induce strong local electromagnetic field enhancements at the plasmon resonance, significantly increasing the Raman signal or fluorescence of a molecule. Inspired by moth eyes, metal nanoparticle arrays can reduce the reflection of incident light, shown useful for improving the efficiency of solar cells. Here, we present fabrication of robust, tunable, inexpensive and quickly reproducible gold coated, nanopillar arrays for applications in enhancing Raman/fluorescence signals or antireflective surfaces for efficient solar cells. To create homogenous metallic nanostructures with controllable sizes and interparticle spacings, we have integrated conventional nanosphere lithography techniques with thermally responsive polyolefin (PO) films. Spin coating 500 nm PS beads onto PO substrates, followed by oxygen plasma etching, is used to vary the size and periodicity of the resulting PS nanopillar bead array. A 50 nm thick gold film can then be added using chemical vapor deposition (CVD). Nanostructures were characterized with scanning electron microscopy and atomic force microscopy. When heated from room temperature up to 115oC, structures on PO films undergo a reduction in feature size and interparticle spacing by up to 35 % in length and 50% in surface area.

In this work an innovative and low cost optical chemical sensor, based on surface plasmon resonance in plastic optical fiber, is presented and experimentally tested for the detection and analysis of trinitrotoluene (TNT). The fabricated optical chemical sensor was realized removing the cladding of a plastic optical fiber along half the circumference, spin coating on the exposed core a buffer of Microposit S1813 photoresist, and finally sputtering a thin gold film. A Molecularly Imprinted Polymer (MIP) film was deposited on the thin gold film for the selective detection of TNT. It has been found that the sensor recognizes trinitrotoluene, since the SPR signal is affected by the presence of TNT in the polymer, while with a slow response kinetics, probably due to the thickness of the polymeric layer.

Magnetoelectric (ME) thin film composites are attracting a continually increasing interest due to their unique features and potential applications in multifunctional microdevices and integrated units such as sensors, actuators and energy harvesting modules. By combining piezoelectric and highly magnetostrictive thin films, the potentialities of these materials increase. In this paper we report the fabrication of SmFe2 and PZT thin films and the investigation of their properties. First of all, a ~ 400 nm thin SmFe film was deposited on top of Si/SiO2 substrate by magnetron sputter deposition. Afterwards, a 140 nm Pt bottom electrode was sputtered on top of the SmFe film forming a bottom electrode. Spin coating was employed for the deposition of the 150 nm thin PZT layer. A PZT solution with 10 %Pb excess was utilized for this fabrication step. Finally, circular Pt top electrodes were sputtered as top electrodes. This paper focuses on the microstructure of the individual films characterized by X-Ray diffractometer (XRD) and scanning electron microscopy (SEM). A piezoelectric evaluation system, aixPES, with TF2000E analyzer component was used for the electric hysteresis measurements of PZT thin films and a vibrating sample magnetometer (VSM) was employed for the magnetic characterization of the SmFe. The developed thin films and the fabricated double layer SmFe-PZT exhibit both good ferromagnetic and piezoelectric responses which predict a promising ME composite structure. The quantitative chemical composition of the samples was confirmed by energy dispersive spectroscopy (EDX).

Resist spin coating has already been applied to IC industry for a very long time. Uniform spin coat of photoresist has been demonstrated on 12” wafers with conventional 6” and 8” methods. Meanwhile, resist dispense volume reduction has also been widely studied and investigated. In our paper, we focus on the physical properties of photoresist and prewet solvent. We try to figure out the interfacial behavior/mechanism between ArF resist and its related pre-wet solvent by systematic methods and DOE splits. In the experiments, different ArF resists among various solvent systems and two distinct pre-wet systems are tested and researched. Certain ArF resists generate smaller dispense volume compared with other PRs even under the same process condition. Eventually, from the splits we find out the trend which correlates to the interaction between resist and pre-wet solvent. The trend proves that our hypothesis is correct. The conclusion will contribute to our future resist selection. The conclusion will also provide new resist design concept to resist vendors. Basic studies and experiments are carried out under our limited resources, equipment and time. We have tried our best to find out the mechanism and have proved it.

Developing optical resonators with high quality factors, small mode volumes, and high refractive index contrast is important for many integrated optics and communications applications. High quality factors and small mode volumes are especially desirable to maximize the circulating intensity and Purcell factor for laser applications. However, controlling an optical resonator’s mode volume and refractive index contrast can be difficult as they depend primarily on the inherent material properties of the resonator. One approach to reduce mode volume and control refractive index contrast is to apply high refractive index polymer coatings. However, polymer coatings are not compatible with all fabrication processes and not as robust as silica and silicon. Recently, we developed and characterized high refractive index silica films containing small amounts of titanium dopant. The silica films are fabricated using a sol gel method with methyl triethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) precursors. Depending on the amount of titanium added, the refractive index of the resulting film can be tuned from 1.44 to 1.62, as measured by spectroscopic ellipsometry. By spin coating these high index silica films onto silica toroid resonators, we experimentally and numerically obtain a significant reduction in mode volume while maintaining high quality factors. Additionally, the presence of the high refractive index coating allows tuning of the circulating light’s position, shape, and interaction with the coating. Therefore, these high refractive index films offer a useful and more robust method to optimize the properties of optical devices for communications and integrated optics applications.

Quantum dot light-emitting diodes (QD-LEDs) have recently attracted much attention due to its highly saturated emission color and the capability of tuning the emission color by means of engineering its size. In this letter, an allinorganic light-emitting diode based on colloidal core/shell CdS/ZnS nanocrystal quantum dots (QDs) emissive layer sandwiched between p-type NiO and n-type ZnO is reported. NiO and ZnO layers are deposited by means of the lowcost spin coating technique. The device showed a rectification behavior and QD light emission with the electroluminescent emissions at 605nm.

Methodologies to fabricate a solid optical tissue phantom (OTP) mimicking epidermal thin-layer have been developed for in vitro human skin experiment. However, there are cumbersome and time-consuming efforts in fabrication process such as a custom-made casting and calculation of solvent volume before curing process. In a previous study, we introduced a new methodology based on spin coating method (SCM) which is utilized to fabricate a thin-layer OTP analogous to epidermal thickness. In this study, a double layer solid OTP which has epidermal and dermal layers was fabricated to mimic the morphological and optical similarity of human tissue. The structural characteristic and optical properties of fabricated double layer OTP were measured using optical coherence tomography and inverse adding doubling algorithms, respectively. It is expected that the new methodology based on the SCM may be usefully used in the fabrication of double layer OTP. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.