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In this paper we report epoxy molding compound lead frames (EMC-LFs) with encapsulated silicone as a simple and inexpensive packaging for AlGaN-based ultraviolet-B (UVB) light-emitting diodes (LEDs) displaying high light extracting efficiencies (LEE) and long operation lifetimes. The convex surfaces and beveled shapes obtained after curing the encapsulated silicone surrounding the UVB-LED chips significantly enhanced the light output power (LOP). With silicone present inside the EMC-LFs having bonding cavity diameters of 1.7 and 1.45 mm, the LOPs of the UVB-LEDs improved by 26 and 42%, respectively; reliability tests performed over a period of 1000 h revealed, however, that the LOPs decreased to 70 and 71%, respectively, of their initial values, but no cracks appeared in the silicone during such long-term operation. Thus, the stability of silicone-encapsulating EMC-LFs for UVB-LEDs was acceptable. When compared with AlN-based direct plating copper ceramic lead frames (AlN-DPC-LFs), our proposed packaging structure and method have the potential to lower the manufacturing cost of UVB-LEDs.

In this paper, we report an AlN-based ceramic lead frame (LF) with encapsulating silicone between the surface of an AlGaN-based ultraviolet-B light-emitting diode (UVB-LED) chip and a quartz glass cover, the light output power (LOP) of this structure was 13.8% greater than that of the corresponding packaging structure without encapsulating silicone. Another packaging structure in which the silicone fully filled the cavity of the AlN-based ceramic LF included covering with quartz glass, in this case, the enhancement of the LOP was 11.7%. Reliability tests performed over a period of 3500 h at a forward current (If) of 100 mA revealed that the LOPs of these two silicone-containing packaging types decreased to 45.3 and 48.6%, respectively, of their initial values. The different degradation rates of these UVB-LEDs were not, however, correlated with the appearance of cracks in the encapsulating silicone during long-term operation. Excluding any possible mechanisms responsible for degradation within the UVB-LED chips, we suggest that the hermetic cover should be removed to avoid the appearance of cracks. Moreover, the main mechanism responsible for the slow degradation rates of LOPs in these proposed packaging structures involves the encapsulated silicone, after cracks have appeared, undergoing further deterioration by the UVB irradiation.

This work presents a method for obtaining a color-converted red light source through a combination of a blue GaN light-emitting diode and a red fluorescent color conversion film of a perovskite CsPbI3/TOPO composite. High-quality CsPbI3 quantum dots (QDs) were prepared using the hot-injection method. The colloidal QD solutions were mixed with different ratios of trioctylphosphine oxide (TOPO) to form nanowires. The color conversion films prepared by the mixed ultraviolet resin and colloidal solutions were coated on blue LEDs. The optical and electrical properties of the devices were measured and analyzed at an injection current of 50 mA; it was observed that the strongest red light intensity was 93.1 cd/m2 and the external quantum efficiency was 5.7% at a wavelength of approximately 708 nm when CsPbI3/TOPO was 1:0.35.

This paper presents a parallel plate-type field emission device of potassium hydroxide-doped electrochemically reduced graphene oxide (GO) manufactured using highly oriented pyrolytic graphite through electrochemical exfoliation. The material properties of the GO were tested through Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The optimal electron emission characteristics of the device were as follows: turn-on field = 2.03 V/ $\mu \text{m}$ , field emission current $= \,\, 16.4~\mu \text{A}$ , and field emission enhancement factor = 8377. At an emission peak wavelength of 563.7 nm, the optimal device had a light flux of 4.21 lumens and an illumination of 140.3 lux. These properties can be utilized in various optoelectronic devices, such as nanoelectronics devices, sensors, electrochemical systems, and energy storage devices.

The power conversion efficiency (PCE) of an Ag/spiro-OMeTAD/CH3NH3PbI3 (MAPbI3)/PCBM/mesoporous TiO2/compact TiO2/FTO planar solar cell with different annealing temperatures of PbI2 and MAPbI3 films was investigated in this study. The morphology control of a MAPbI3 thin film plays key roles in high-efficiency perovskite solar cells. The PbI2 films were prepared by using thermal vacuum evaporation technology, and the MAPbI3 perovskite films were synthesized with two-step synthesis. The X-ray spectra and surface morphologies of the PbI2 and MAPbI3 films were examined at annealing temperatures of 80, 100, 120, and 140 °C for 10 min. The performance of the perovskite planar solar cell at an annealing temperature of 100 °C for 10 min was demonstrated. The power conversion efficiency (PCE) was about 8.66%, the open-circuit voltage (Voc) was 0.965 V, the short-circuit current (Jsc) was 13.6 mA/cm2, and the fill factor (FF) was 0.66 by scanning the density–voltage (J–V) curve.

Improved performances of organic optoelectronic devices doped with different Rubrene concentrations were obtained. In the organic light emitting devices (OLEDs), the performance can be improved with the doped Rubrene concentration of 5wt%, which yields a maximum luminance of 0.14 cd/m2, a threshold voltage (Vth) of 10.4 V. In organic solar cells (OSCs), the power conversion efficiency (PCE) of OSCs active layer with the poly(3-hexylthiophene) (P3HT) and P3HT: -(3-methoxycarbonyl)- ropyl-1-phenyl- (6, 6) C 61 (PCBM) doped with 3.5wt% Rubrene, have much better PCE than the one without Rubrene with 1.66 times and 2.15 times, respectively. It is found that the best properties that the P3HT: Rubrene OSCs with open-circuit voltage (Voc) 0.62 V, short-circuit current (Isc) 1.91E-4 mA and PCE of 8.5E-5% was achieved under the air mass 1.5 global (AM 1.5G) illumination of 100 mW/cm2.

Raman spectrum of a graphene edge, showing the main raman features, the D band(˜1350 cm-1), G band(˜1580 cm-1) and 2D band (˜2700 cm-1) taken with a laser excitation energy of 2.41 eV. D band is not easy to be found in the good structure of the graphite, generally D band and G band integral intensity ratio ID / IG, to determine whether the carbon material defects and the crystallization of the pros and cons, but D band is usually also the incident light wavelength with the impact of the incident area. The insert voltage conditions with H2SO4 and KOH is demo in the study. The D band and G band integral intensity ratio ID/ IG is equal 1.08, and FWHM(cm-1) is equal 97.6 value.

This letter describes the successful fabrication of a novel tri-layer Ag/SiO2/Ag plasmonic thermal emitter with circular and square hole shapes at top silver film arranged in a hexagonal dimple array. The proposed design improves the emission intensity and reduces the full width half maximum. Experimental results indicate that the proposed design increases the emission intensity at 200°C from 30.5 to 42.3 mW/cm2 for the hexagonal circular hole array, as well as increases the same intensity from 43.3 to 79.3 mW/cm2 for the hexagonal square hole array.

The enhanced transmission of higher order plasmon modes with random gold nanoparticles embedded in periodic hole arrays using asymmetric pair aperture as a unit is investigated in the midinfrared regime. Different thicknesses of gold film were deposited inside holes and then annealed to form randomly sized and distributed nanoparticles. The holes deposited with thin gold film exhibit significantly enhanced transmission in higher order modes after thermal annealing. The enormous local electric field around the nanoparticles enhances the scattering effect that contributes to the enhanced infrared transmission. This unique design, which integrates localized and propagating surface plasmons, provides an easy way for midinfrared applications in need of enhanced transmission in higher order modes.

In electrophoretic deposition, the quality of the deposition is closely related to both the electrolyte and electric field intensity. This study involved modifying the traditional electrophoresis setup and adjusting the variables of an experiment to deposit higher quality graphene a non-conductive silicon substrate. With a DC bias of 30 V and a 1 wt% Al2 (SO4)3 electrolytic solutions, the highest amount of graphene and the lowest number of graphene defects can be obtained. The defect ratio ID/IG is approximately 0.95.

In the experiments of electrochemical exfoliated graphene, the insert voltage1∼3V and electrolyte composition of 2.4g sulfuric acid, 0 ∼5 mL of 30% KOH and 100 mL of deionized water should were changed to find their relationship with graphene defects. Analysis of Raman spectra illustrated that using a lower insert voltage and a OH−: H+ ratio for the electrolyte of 1:2 reduced the number of defects. Its defect ratio ID/IG was 0.5.

Field emission device of graphene oxide (GO) with parallel plate-type structure was successfully produced with highly oriented pyrolytic graphite (HOPG) by electrochemical exfoliation. The material, chemical characteristics and material surface structure were analyzed with Raman spectroscopy, XRD, SEM and XPS as well. The best field emission enhancement factor β is 1878.5, and the turn-on field defined current equals to 1μA, max emission current are 3.73V/μm and 12μA, respectively. GO is a good candidate for field emission device.

This paper presents electrodeposition of diamond-like carbon (DLC) thin film deposits on indium tin oxide (ITO) glass substrate under voltage 2.1V∼120V with mixing varying acetic acids' portions with deionized water, forming 0.2∼0.8% electrolytic solutions. The result shows that at deposition temperature 30°∼65°, voltage 50V and 0.8% electrolytic solution concentration of DLC thin films, the reflection index reduced to 60%, and theoretical matching refractive index became 1.32. This finding is applicable on various optoelectronic device like protective or window layer of solar cell.

A low dropout regulator with super-source follower is exhibited and a single-transistor-control low dropout based the flipped voltage follower is discussed in this paper. The buffered flipped voltage follower with super-source follower is proposed to lower its output impedance so that the impedance at the gate of the pass device can be reduced and the pole at the gate is pushed to higher frequency as well as. The proposed low dropout with super-source follower is designed and simulated in TSMC 0.18 µm CMOS technology process. The layout design area is 565µm „e 508µm. It can be obtained that when power supply voltage Vdd is 3.3 V, the circuit can provide the output voltage of 1.999 V and the power consumption of 15.94 mW with a variation of 4 mV in a load current range from 2 mA to 100 mA.

Organic solar cells of Al / P3HT / PEDOT: PSS / Indium tin oxide (ITO)/ substrate with different substrates were fabricated and characterized. The most effective efficacy of organic solar-cell on borosilicate substrate with parameters was improved, which yields an open-circuit voltage of 0.778V, a short-circuit current of 3.37E-07, a fill factor of 12.7% and a power conversion efficiency of 1.34E-04% under the AM 1.5G illumination of 100 mW/cm2. Its efficiency increased up to decuple than organic solar-cell on silicate substrate.

This investigation elucidates the transmission characteristics of an Ag-Si structure on which an Ag film is perforated with a rhombus-shape of lattice holes. The transmission in the Ag-Si mode depends approximately linearly on the numbers of degenerate modes at long wavelengths at which the couplings between Ag-Si and Ag-air modes are weak. At the shorter wavelengths where Ag-Si and Ag-air modes are coupled together, the transmission intensities are approximately constant without an apparent peak at wavelengths longer than those of the Ag-air modes. The intensities decay rapidly at lower wavelengths owing the asymmetric slope of the Ag-air mode in the spectra.

This work describes innovative waveguide thermal emitters with top metal perforated with subwavelength holes arranged in a short period to eliminate Bragg scattered waveguide modes (WMs) and surface plasmon polariton (SPP) modes. A metal-dielectric-metal parallel-plate waveguide with top metal perforated with subwavelength holes arranged in a short period exhibits high output intensities and emission peaks (WMs) with a narrow bandwidth in the midinfrared region under heat treatment. The redundant SPP modes and Bragg scattered WMs are filtered automatically by shifting them to the short wavelength due to a short period where blackbody radiations are too weak to appear.

The two-color quantum-dot infrared photodetector (QDIP) has been fabricated successfully by the use of top metal contact perforated with cross hole arrays. One transmission peak is located at 4-6 ?m; the other is located at 8-10 ?m . The periodic contact metal hole arrays play double roles, i.e., the top contact and the optical filter. Patterning with lattice constants a = 1.6 ?m and a = 2.8 ?m, the 4- to 6-?m and 8- to 11-?m wavelength ranges can be detected. The two-color QDIP detectivity can be increased up to 1.85 ×1011 cmHz1/2/W at 20 K and the background limited temperature is between 60 K-70 K. It can be applied to fabricate focal plane arrays.

Coherent phonon spectroscopy of GaInP/GaAs/GaInP single quantum wells is demonstrated with time-resolved second-harmonic generation. Coherent longitudinal optical phonons are impulsively launched via transient pump-induced field screening and stimulated Raman scattering in the well and barrier regions. A phonon mode at 9.4 THz is identified as interfacial phonon localized in the GaAs/GaInP hetero-interface. The free induced dephasing of this coherent interfacial phonon is analyzed with window-gated Fourier transform. Its dephasing time is used to characterize the interface quality of semiconductor heterostructures.

A plasmonic thermal emitter with a periodic block pattern as the top layer was investigated. It is found that by adjusting the length and orientation of the rectangle metallic islands inside the block pattern, three polarization-dependent peaks can be obtained in the thermal radiation spectra. The individual mode can be extracted according to the different polarizations by an external polarizer. In addition, the device can be designed to emit in the desired wavelength range by tuning the dimensions of the block pattern.

The application of double-walled carbon nanotubes on amorphous silicon solar cell to improve light trapping and shift the surface plasmon from periodic nanostructure is proposed. A thin film of double-walled carbon nanotubes is coated on the hexagonal nanostructured silver film and uses as the back reflector of solar cells. Based on the periodic Ag nanostructure, the surface plasmon is constructed; with the addition of double-walled carbon nanotubes on the Ag nanostructure, the surface plasmon is red shifted owing to the changing environment around the surface and the light scattering effect is improved due to this rough surface. Our results suggest that by controlling the DWCNTs density on Ag nanostructure, the performance of the short-circuit current and power conversion efficiency can be enhanced‥

Extraordinary transmission through metallic film perforated by periodic holes array is often induced by surface plasmon. However, the non-centrosymmetric trumpet shaped holes enhance localized resonance inside the trumpet cavity. The measured results of the transmission and reflection spectra of Ag/Si and Ag/SiO 2 /Ag structures, respectively, reveal that spectral peaks shift according to the size of the trumpet cavity but not the period of the array indicating the localized nature of the resonant modes. The interaction between Wood's anomaly and LSRs were described directly. Moreover, the reflection spectra reveals double (1,0)Ag/SiO 2 LSRs inside.

Optical emission spectra of the tri-layer Ag/Al 2 O 3 /Ag plasmonic thermal emitter with square and hexagonal lattice are consistent with the extraordinary transmission through Ag/Si structure with similar lattices. The plasmonic thermal emitter with hexagonal periodic lattice emits only one strong (1,0)Ag/Al 2 O 3 peak, tends to suppress the (1,0)Ag/air and (1,1)Ag/Al 2 O 3 SP modes, whereas a similar plasmonic thermal emitter with square periodic lattice emits two strong (1,0) and (1,1)Ag/Al 2 O 3 peaks, their relative intensities follow the blackbody radiation law. Its fits well to the transmission spectra of the Ag/Si structure with square and hexagonal lattice, the (1,0)Ag/air and high order Ag/Si Rayleigh-wood's anomaly, the (1,0)Ag/air and (2,0), (2,1)Ag/Si SP modes were excited when the holes cover more than 12.6%or 14.5%of the total area of the Ag film, respectively.

Enhanced optical transmission through an Al film with perforated short-range 3times3, 4times4 and 5times5 hole arrays arranged in a long-range periodic structure is investigated. This three finite squared holes array constitutes an individual micro-cell, respectively. The measured transmission peak wavelength reveals that the surface plasmons are Fabry-Perot type resonance to different integer order. The ratio of periodicity between the super-periodic structure p and the NtimesN micro-cell d determines the integer order (where N is number of isolated hole; N=3, 4 and 5). Namely, when p/d>4, the order 4 and 5 surface plasmon modes with average hole spacing p/4 and p/5 are observed in 4times4 micro-cell array, respectively. The transmission intensities of order 4 mode are the strongest, and those of order 5 modes are barely seen. But as p/d approaches 5, the order 4 mode gradually disappear with the emergence of order 5 mode. The 3times3 and 5times5 micro-cell array have the same result. These phenomena suggest that the surface plasmons are Fabry-Perot type resonance within a super unit cell. The dispersion relations of surface plasmons are also observed.

The emission spectra of Ag∕SiO2∕Ag trilayer plasmonic thermal emitters with various SiO2 thicknesses were investigated. By analyzing the relationship between emission peaks and thicknesses of SiO2, the coupling of surface plasmons between two silver films in a plasmonic thermal emitter is demonstrated and the coupling length is determined as well. Furthermore, the dispersion relation of plasmonic thermal emitter is detected by measuring the reflection spectra with various incident angles. This confirms that the main mechanism involved in the emission of a plasmonic thermal emitter is due to the excitation of surface plasmons.

The enhanced and suppressed optical transmission through aluminum metal with periodic micro-cells (with 3 × 3 [unk] 6 × 6 [unk] 9 × 9 [unk] 12 × 12 and 16 × 16 hexagonal holes array) arranged in a random structures were investigated. The random structure allows multi-peak transmission by adding micro-cells with different lattice constants. Since the periodic structure has only one peak transmission wavelength, the random structure provides multi-color light transmission properties which can be applied to wavelength selective infrared device.

The zero-order transmission of radiation through a metal/dielectric structure perforated with square hole arrays is strongly enhanced when incident light resonates with surface plasmons (SPs). Surprisingly, when a metal/dielectric double layer, such as Ag/SiO 2 , is fabricated on a silicon substrate, the Ag/Si SP mode by coupling Ag and Si across the intermediate dielectric film has been found. The transmission intensity is investigated as a function of the intermediate SiO 2 thickness. The coupling lengths between Ag and Si in order to form the Ag/Si SP mode are determined as well.

A thermal emitter with narrow bandwidth emission property is very useful in the studies of the reaction of biological system to the infrared light. This invention of plasmonic thermal emitter is aimed at providing such narrow bandwidth infrared light emitting source by sandwiching an insulating layer between two metal films and forming regular array of holes in the upper metal to enhance the thermal radiation spectrum of specific wavelengths. Besides, the background thermal radiation can be suppressed by this structure. It was demonstrated that when the central SiO 2 layer of the sandwiched structure is flat without holes, the emission spectrum is narrower than that of the perforated one. Two emission peaks from Ag/SiO 2 and Ag/Air surface plasmon polaritons can be clearly seen.

This study investigates a Au/SiO2/Au waveguide thermal emitter incorporating a metallic grating embedded in the SiO2 layer. The metal grating acts as a beam splitter, dividing the device into two waveguide structures determined by the polarization of the waveguide modes. The thermal radiation spectrum exhibits two peaks with orthogonal polarization. The emitted wavelengths of the two waveguide modes can be adjusted by controlling the thickness of the SiO2 layers on both sides of the metallic grating during the fabrication process. The emission peaks have ratios of the full width at half maximum to the peak wavelength of 0.057 and 0.05 for the TE and TM polarizations, respectively. These characteristics show the suitability of the device for multi-peaks and narrow bandwidth infrared light source applications.

We have employed electric-field-induced second-harmonic (EFISH) generation to determine the flat-band voltage (VFB) of Cr/ALD-Al2O3/MBE-HfO2/n-Si (001) MOS structure. Due to the phase sensitivity of EFISH signal to the electric field in the space charge region, the VFB of −1.20±0.07 V was determined by analyzing the relative phase change in the EFISH signal as a function of the applied gate voltage. The obtained value is in good agreement with that estimated by the capacitance-voltage measurement. This study demonstrated an all-optical technique to directly determine the flat-band voltage for the high κ oxide/Si heterointerfaces.

The experimental results of light transmission through periodic array of H-shaped hole and more complicated hole which is a combination of multiple U shape are demonstrated. The observations indicate that the localized shape resonance in the longest resonant length of unfolded U-shaped part of the hole always appears. However, localized modes resonant in smaller U-shaped length don't always appear. Localized mode with non-U-shaped resonant path cannot be seen in our sample. In addition, localized mode with different order and resonant path can be excited by different polarized light.

The experimental results of dispersion relations and thermal emittance spectra of a metal/insulator/metal (MIM) structure with rectangle metallic patch arrays as top layer are demonstrated. The structure exhibits wide-angle, multipeak and polarized emission characteristics caused by Fabry-Perot type resonances of surface plasmons. Emission modes in x- and y-polarization are totally distinct, and their position depends on the width and length of the rectangular metallic patch. Therefore the designing of mode positions has two degrees of freedom and could be applied to wavelength selective light sources.

Polarized infrared thermal emitters consisting of a waveguide thermal emitter combined with silver grating structure were studied. For a device containing a perforated silver film under the grating, polarized infrared light was emitted only when the wavelength satisfied the standing wave condition, therefore the broad bandwidth SiO2 phonon vibration modes were suppressed in the thermal radiation spectrum. The polarized ratio with different grating thickness was investigated and the highly polarized ratio up to 0.875 was achieved. This study demonstrated that the integrated structure can be used as a narrow bandwidth and highly polarized ratio infrared light source.

The emission spectra of the trilayer Ag/dielectric/Ag plasmonic thermal emitter (PTE) with different lattice type, hole shape, and dielectric material were investigated. It is found that the position and number of thermal emission peak of the PTE are determined by the lattice type not by the hole shape and dielectric materials. The PTE with hexagonal lattice generates only one strong (1,0) Ag/dielectric emission peak, whereas a similar PTE with square lattice generates two strong (1,0) and (1,1) Ag/dielectric emission peaks, their relative intensities follow the blackbody radiation law. This phenomenon suggests the coupling of Ag/dielectric and Ag/air modes.

The experimental results of linear polarized light transmitting through an array of Archimedean spiral slots perforated on a thin metal film in the far-infrared region are demonstrated. The wavelength selective transmission spectra are examined, and the polarization selective shape resonance will lead to the polarization rotation. The sign of rotation not only depend on the handedness of the spiral but also related to specific initial polarization position. This phenomenon is different from the conventional optical activity in three-dimensional chiral molecules but rather similar to the polarization selective features in rectangular or elliptical slots.