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We report the growth, structural characterization, and transport studies of Bi2Se3 thin film on single crystalline silicon (Si), Si/SiO2, quartz, and glass substrates by thermal evaporation method. Our results show that 300 °C is the optimum substrate temperature to obtain the c -axis (001) oriented Bi2Se3 films on all the substrates. The film grown on the Si substrate has the minimum crystalline disorder. The energy-dispersive x-ray spectroscopy results show that film on Si substrate is bismuth deficient, the film on Si/SiO2 substrate is selenium deficient, and the film on quartz substrate is near perfect stoichiometric providing a way to tune the electronic properties of Bi2Se3 films through substrate selection. The film grown on quartz shows the highest mobility (2.7 × 104 cm2 V-1s−1) which drops to 150 cm2 V-1s−1 for Si, 60 cm2 V-1s−1 for Si/SiO2, and 0.9 cm2 V-1s−1 for glass substrate. Carrier concentration is n-type for Bi2Se3 films on Si (∼1018 cm−3), quartz (∼1018 cm−3) and Si/SiO2 (∼1019 cm−3) substrate with a clear indication of frozen out effect around 50 K for Si/SiO2 and Si substrate. Longitudinal resistivity of Bi2Se3 film on Si/SiO2 substrate shows different behavior in three different temperature regions: temperature dependent resistivity region due to electron–phonon scattering, a nearly temperature independent resistivity region due to electron–phonon and electron–ion scattering, and a quantum coherent transport region. [ABSTRACT FROM AUTHOR]

The authors propose and demonstrate that thermal laser evaporation can be applied to all solid, nonradioactive elements in the periodic table. By depositing thin films, they achieve growth rates exceeding 1 Å/s with output laser powers less than 500 W using identical beam parameters for many different elements. The source temperature is found to vary linearly with the laser power within the examined power range. High growth rates are possible using free-standing sources for most of the elements tested, eliminating the need for crucibles. [ABSTRACT FROM AUTHOR]

The grain size evolution of polycrystalline thin films, which form by competitive grain overgrowth as commonly interpreted using the van der Drift model, is understood to follow a power-law scaling of the average grain size d with film thickness h , i.e. d ∝ h α . While simulations have identified a growth exponent α = 0.4 for three-dimensional growth, previous experimental studies did not confirm this value, instead finding α values in the range of ∼0.5–0.7. Here we study competitive grain overgrowth using a system of ZnO thin films grown by low-pressure metal–organic chemical vapor deposition. We present quantitative data on the evolution of grain size and orientation across the thickness of thin films, obtained by automated crystal orientation mapping of "double-wedge" transmission electron microscopy samples. The data from a -textured ZnO films, grown under three different conditions, are compared against van der Drift model predictions of self-similarity of the grain size distribution and the power-law scaling. The results are further interpreted by comparing to simulations of faceted polycrystalline film growth, which we adapt to the ZnO system by including idiomorphic growth shapes with a six-fold symmetry and random or biased nuclei orientations. As well as showing the predicted self-similarity of grain size distributions during growth, for the first time our experimental data confirm a power-law growth exponent of α = 0.4, as also predicted by the simulations using randomly oriented nuclei. Nevertheless, interpretation of this result is contingent on the absence of factors such as textured nucleation and renucleation during film growth. Indeed, only one film, grown at a higher ratio of H 2 O/DEZ precursor gases, displaying random initial nucleation, and minimal grain renucleation during growth, shows a proper conformance to the model nature and predictions. Image 1 [ABSTRACT FROM AUTHOR]

Dynamic in-situ spectroscopic ellipsometry (iSE) was employed to investigate the growth mechanism of the tantalum oxide (TaO) film on silicon wafer substrate deposited by reactive gas-timing RF magnetron sputtering compared with conventional reactive sputtering. The effect of reactive gas timing parameter on physical structure and optical property were analyzed by both the continuous and island film growth model with Tauc-Lorentz optical model. The variation of refractive index, film thickness and void volume fraction were obtained from dynamic fits of iSE data indicated that the growth process of the amorphous TaO thin films was divided into two regimes: the nucleation stage and continuous-layer stage. These stages were observed during deposition although the initial film growth stage corresponds to the island film growth model. The study demonstrates that sputtered TaO by the RGT technique at the O 2 on-off gas timing has played a crucial factor in improving the formation of nucleation stage and that the deposited TaO thin films were high deposition rate with high refractive index. The complementary field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) showed a good agreement with the film thickness and morphology obtained from dynamic iSE measurement. The real-time monitoring of iSE offers important evidences to understand the growth mechanism of reactive gas-timing technique. • Tantalum oxide thin films were deposited by reactive gas-timing RF magnetron sputtering compare. • The film growth process of the sputtered TaO thin films were studied using dynamic iSE. • The O 2 on-off gas timing has played a crucial factor in improving the formation of nucleation stage. • The deposition rate, refractive index and void volume fraction depends on the on–off gas-timing sequence. • The dynamic iSE results shows good agreement with the complementary FE-SEM and TEM measurements. [ABSTRACT FROM AUTHOR]

Highlights • Real-time in-situ investigation of copper films growth. • Optical properties change depending of film thickness recorded and compared with modelled values. • All stages of Volmer-Weber growth mode recorded. • New empirical method to determine in-situ the minimum thickness of the continuous films proposed. Abstract The results of real-time in-situ spectroscopic investigation of copper films growth are presented. The films were deposited on fused silica substrates by magnetron sputtering. Three growing stages of copper films were in-situ, ex-situ analysed and compared with modelled values. The minimum continuous film thickness of about 10 nm was determined by such comparison. This new empirical method might be applied for multilayer coatings deposition. [ABSTRACT FROM AUTHOR]

A new technique for the parallel collection of X‐ray reflectivity (XRR) data, compatible with monochromatic synchrotron radiation and flat substrates, is described and applied to the in situ observation of thin‐film growth. The method employs a polycapillary X‐ray optic to produce a converging fan of radiation, incident onto a sample surface, and an area detector to simultaneously collect the XRR signal over an angular range matching that of the incident fan. Factors determining the range and instrumental resolution of the technique in reciprocal space, in addition to the signal‐to‐background ratio, are described in detail. This particular implementation records ∼5° in 2gθ and resolves Kiessig fringes from samples with layer thicknesses ranging from 3 to 76 nm. The value of this approach is illustrated by showing in situ XRR data obtained with 100 ms time resolution during the growth of epitaxial La0.7Sr0.3MnO3 on SrTiO3 by pulsed laser deposition at the Cornell High Energy Synchrotron Source (CHESS). Compared with prior methods for parallel XRR data collection, this is the first method that is both sample‐independent and compatible with the highly collimated, monochromatic radiation typical of third‐generation synchrotron sources. Further, this technique can be readily adapted for use with laboratory‐based sources. [ABSTRACT FROM AUTHOR]

Zinc sulfide (ZnS) thin films deposited by chemical bath deposition (CBD) technique have proved their capability in a wide area of applications including electroluminescent and display devices, solar cells, sensors, and field emitters. These semiconducting thin films have attracted a much attention from the scientific community for industrial and research purposes. In this article, we provide a comprehensive review on the effect of various parameters on various properties of CBD-grown ZnS films. In the first part, we discuss the historical background of ZnS, its basic properties, and the advantages of the CBD technique. Detailed discussions on the film growth, structural and optical properties of ZnS thin films affected by various parameters, such as bath temperature and concentration, deposition time, stirring speed, complexing agents, pH value, humidity in the environment, and annealing conditions, are also presented. In later sections, brief information about the recent studies and findings is also added to explore the scope of research work in this field. [ABSTRACT FROM AUTHOR]

The application of the Voronoi tessellation for studying the nucleation process at the basis of thin film formation dates back to the end of nineties. In particular, Poissonian and spatial correlated nuclei distributions were investigated. The growth of stressed interfaces, however, has evidenced that elastic strain can modify the spatial distribution of nuclei giving rise to new challenges at the level of stochastic geometry. Here we report a study of a 2D nucleation of dots randomly arranged in lines and/or belts on the surface. The results are compared to the experimental case of multilayer structures of InAs quantum dots grown on GaAs ( 001 ) . [ABSTRACT FROM AUTHOR]

The Be films were prepared on the water-cooled substrates and heated substrates by thermal evaporation, respectively. The experiment of water-cooled substrate showed the grains in Be films grown on Si substrates were refined than those grown on glass substrates and the surface roughness of Be films grown on Si substrates was also improved. The electrical performance test suggested that the electrical resistivity of Be films grown on water-cooled substrates decreased with increasing the heating temperature and was bigger than that grown on non-water-cooled substrates. For the experiment of heated substrate, the Be films appeared the loose flocculent structure, and the surface roughness firstly increased from 8 nm to 45–65 nm in the range of 150–300 °C and then decreased to 10 nm at 400 °C. Meanwhile, its electrical resistivity sharply increased from 0.6 Ω/□ to 206.6 Ω/□ due to the gradual oxidization at high temperature, especially 400 °C. [ABSTRACT FROM AUTHOR]

• Uniform BaF 2 films were achieved after adjusting pulsed laser deposition conditions. • Eu-doped layered nanocomposite thin films with controlled thickness were deposited. • BaF 2 layers changed from amorphous to nanocrystalline with increased thickness. • Photoluminescence emission from Eu3+ ions was observed in the nanocomposite films. • Emission intensity was affected by crystallinity and crystal size in BaF 2 layers. We have developed a pulsed laser deposition (PLD) geometry for the growth of uniform BaF 2 nanoscale thin films, through control of the deposition conditions. Our goal is to use the BaF 2 layers with controllable structure as component layers in layered optical nanocomposites. The structure of the BaF 2 nanolayer evolves as a function of the layer thickness: BaF 2 grows via a layer-by-layer growth mode on Al 2 O 3 ; the layers are amorphous for a thickness < 3 nm, and then become nanocrystalline as the layer thickness increases. The BaF 2 nanocrystals have an FCC crystal structure with a weak <111> texture that becomes stronger for thicker films. We then demonstrate that our BaF 2 films can be introduced into layered Al 2 O 3 /BaF 2 /EuO x nanocomposite films, which allows for control of the relative position of the Eu ions and the BaF 2 layer. Cross-section samples of the multilayered films show interfacial intermixing between the layers, which is related to implantation during the PLD process. This intermixing enables the incorporation of Eu ions into BaF 2 layers and form a thin Eu-doped BaF 2 nanolayer at the interface. The layered nanocomposite films show photoluminescence (PL) emission from Eu3+ ions, and the PL intensity changes can be correlated with the crystallinity and crystal size changes in the BaF 2 layer. Our results provide guidance for achieving thin film nanocomposite materials with controllable structure and photoluminescence behavior for light emitting diodes, photovoltaics and other optical applications. [ABSTRACT FROM AUTHOR]

We measure absorption spectra of two different perylene molecules in thin films with thicknesses varied between 1 and 30 nm physical vapor deposited on glass substrates. Atomic force microscopy (reveals the formation of crystallized needles for N, N`-dimethyl perylene tetracarboxylic acid diimide and amorphous round-shaped islands for 1,6,7,12-tetrachloro-N,N`-dimethyl perylene tetracarboxylic. For both molecules, a spectral shift of the lowest energy transition to lower energies was observed with increasing film thickness. Common models taking electric fields, electronic coupling or exciton confinement into account cannot completely describe the observed spectral shift. Here we show that the experimental values can be fitted with an advanced layering model based on the energetic difference between bulk and interface/surface materials. In contrast to the known simple d − 1 model, which describes the energetic shift for the special case of a layer-by-layer growth, we extend this idea to other film morphologies. [ABSTRACT FROM AUTHOR]

Highlights: [•] CZTS films were fabricated by sulfurizing the fabricated precursor films. [•] Annealing time and temperature are very important for synthesis of pure CZTS films. [•] Pure CZTS films with high quality can prepared at 500°C and 90min. [•] Both high temperature and long heating time causes the decomposition of CZTS films. [ABSTRACT FROM AUTHOR]

Highlights: [•] Growth of thin layers of PDI8-CN2. [•] In situ monitoring of optical absorbance during film growth. [•] Spectral shifts modeled by coupling of transition dipole moments. [•] Correlation of findings with molecular structure and orientation in the lattice. [•] Dominance of intralayer vs. interlayer coupling. [ABSTRACT FROM AUTHOR]

To validate the correctness of the Hartman-Perdok Theory (HPT), which indicates that the {111} planes have the lowest surface energy in spinel ferrites, the {111} plane orientated ZnFeO thin films on Si(100), Si(111), and SiO(500 nm)/Si(111) substrates were obtained through a radio frequency (RF) magnetron sputtering method with a low sputtering power of 80 W. All of the experiments prove that the atom energy determined by sputtering power plays an important role in the orientated growth of the ZnFeO thin films, and it matches well with HPT. The ZnFeO thin films exhibit ferromagnetism with a magnetization of 84.25 kJ/mol at room temperature, which is different from the bulk counterpart (antiferromagnetic as usual). The ZnFeO thin films can be used as high-quality oriented inducing buffer layers for other spinel (Ni, Mn)Zn ferrite thin films and may have high potential in magnetic thin films-based devices. [ABSTRACT FROM AUTHOR]

Abstract: We made Cu2ZnSnS4 (CZTS) thin films by sulfurization of Cu/Sn/Cu/Zn metallic films. Sulfurizations were carried out under different thermal annealing conditions, where maximum temperatures were 440 °C (LT-CZTS) and 550 °C (HT-CZTS). For LT-CZTS films, secondary phases such as SnS2 and Cu2−x S were observed, whereas for HT-CZTS films secondary impurities were not detected. Chemical composition of LT-CZTS film was observed to be very non-uniform. Highly Sn-rich and Zn-rich regions were found on the film surface of LT-CZTS. However, averaged chemical composition for larger area was close to stoichiometry. The HT-CZTS film showed homogeneous structural and chemical composition features. But, for HT-CZTS film, the Sn composition was observed to be decreased, which was due to the Sn-loss. By UV–Visible spectroscopy, optical band gaps of LT- and HT-CZTS films were measured to be ∼1.33 eV and ∼1.42 eV, respectively. The band gap of LT-CZTS film was also observed to be smaller by photoluminescence measurement. The depressed band gap of LT-CZTS film may be ascribed to some defects and low band gap impurities such as Cu2SnS3 and Cu2-xS in the LT-CZTS film. [Copyright &y& Elsevier]

Abstract: Fe(Se1− x Te x ) thin films on (100) SrTiO3 were fabricated by a pulsed laser deposition method, and their crystal orientation, compositional shifts and superconducting properties were characterized by X-ray diffraction, scanning electron microscope combined with energy dispersive X-ray spectroscopy, etc. Compositional shift is one of the major problems during the fabrication of Fe(Se1− x Te x ) films due to its containing high volatile elements such as Se and Te. The compositional shifts were found dependent on the Ar background gas pressure (P Ar), which was suppressed by the increase of P Ar. In addition, it was revealed that the temperature window for the crystallization of the films was shifted to higher temperature region and wider temperature range with the increase of P Ar. [Copyright &y& Elsevier]

Abstract: Electrochemical, metal-centred partial oxidation of the electrodeposited d8 Ru–Ru bonded chain [Ru0(bpy)(CO)2] n results in high electrical conductivity on the order of 10−1 Scm−1. The partial oxidation of Ru0 is reversible in presence of charge-compensating and anions, and quartz crystal microbalance data show that the doping/undoping process is accompanied with transfer of unsolvated electrolyte anions. For and Cl− the process is more complex and in the chloride-case the doping results in break-up of the polymer film. The conductivity of the film is linearly dependent on the electrochemically controlled doping level. Spectroscopic evidence for charge delocalisation is obtained in the near-IR region, with the absorbance proportional to the doping level. The conduction process is thermally activated and ohmic behaviour is found for films both in electrolyte and gas phase. The microscopic structure of dry polymeric films is studied by SEM and anisotropic growth of cone-shaped columns is found. Linear increase in film thickness with deposition charge is obtained above 20μm with a volume yield corresponding to a density 90% of the X-ray diffraction derived value reported in literature. [Copyright &y& Elsevier]

Abstract: The growth of CdS thin films by close space sublimation (CSS) has been systematically studied using an ultra-high vacuum system known as DAISY-SOL in order to understand the basic growth mechanisms and their impact on the film properties. Substrate temperature and deposition rate were varied, and the surface properties of the CdS layer were determined by photoelectron spectroscopy (XPS) without breaking the vacuum. To analyze the influence of the deposition conditions on the layer morphology and crystallographic structure, the films were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM studies show a correlation between the deposition rate and the film morphology. For high deposition rates, edged grain shapes and smoother surfaces were observed than for low deposition rates. CdS films were deposited onto two different commercially available fluorine-doped tin oxide (FTO) substrates. XRD studies show that a high <200> texture of the FTO substrate prefers the CdS growth in <0001> orientation of the hexagonal crystal modification. [Copyright &y& Elsevier]

Abstract: Films of F16PcCu prepared by physical vapor deposition under high vacuum conditions were characterized from the monolayer range up to 40nm thickness. The charge carrier mobility in the saturation regime of the output characteristics and the threshold voltage as well as the on/off-ratio were determined during film preparation. The substrate consisted of a n++-doped Si wafer as gate electrode with a thermally grown SiO2 layer as gate dielectric and photolithographically structured films of gold or silver as source and drain electrodes. F16PcCu formed a conductive channel in the interface region at about 2nm average film thickness. In the subsequent regime of layer formation up to about 8nm a constant charge carrier mobility was established. The threshold voltage considerably decreased during this period of growth and reached a stable level. Subsequent island formation on top of this channel led to only minor changes in the transistor characteristics although the conductivity along the complete organic thin film decreased considerably. By such in situ characterization different contributions of interfacial and bulk transport could be determined and used to optimize films to be used in organic field effect transistors. Ultrathin films of F16PcCu further showed a considerably faster stabilization of the mobility upon exposure to air, the highest on/off ratios and therefore provide clear advantages for device applications. [Copyright &y& Elsevier]

Cadmium sulfide (CdS) thin films have been deposited on glass/conducting glass substrates using low-cost chemical bath deposition method. The deposited films have been characterized using various techniques in order to optimize growth parameters. It has been confirmed by X-ray diffraction measurement that the deposited layers are mainly consisting of CdS phase. The PEC measurements indicate that the deposited CdS layer is n-type in electrical conduction, and optical absorbance measurements show that the band gap is 2.42 eV for as-deposited film and 2.27 eV upon heat treatment for one hour in air ambient. Both atomic force microscopy and scanning electron microscopy measurements indicate the formation of pinhole free and smooth surface of CdS films of nanosized grains. The electrical resistivity is also observed in the order of 1044 Ω cm and decreases as temperature increases. [ABSTRACT FROM AUTHOR]

The measured peak shape and intensity of the photoemitted signal in X-ray photoelectron spectroscopy (XPS) experiments (elastic and inelastic parts included) are strongly correlated, through electron-transport theory, with the depth distribution of photoelectron emitters within the analyzed surface. This is the basis of so-called XPS peak-shape analysis (also known as the Tougaard method) for non-destructive determination of compositional in-depth (up to 6–8 nm) profiles. This review describes the theoretical basis and reliability of this procedure for quantifying amounts and distributions of material within a surface. The possibilities of this kind of analysis are illustrated with several case examples related to the study of the initial steps of thin-film growth and the modifications induced in polymer surfaces after plasma treatments. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) is one of the main methods for elemental and bonding-state characterization in the near-surface region. Applying it as angle-resolved XPS (ARXPS), it is promising for non-destructive depth profiling in the nanometre-thickness range. The challenges for the application of ARXPS are discussed for the early film growth of Ti and Ta on SiO2 produced by in situ magnetron sputtering. The measurements showed several phase-formation processes at the interfaces, which were used as the basis for the ARXPS data analysis and resulted in different interlayer growth information for Ti and Ta. From a systematic ARXPS data interpretation in combination with simulations, limits of the method are critically discussed. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: In order to understand the origin of the residual stress state in thin films and its thickness dependence, the structure–stress relation of magnetron-sputtered Cr and CrN layers with thicknesses ranging from 100nm to 3μm was investigated in detail. Based on correlations between the layer-thickness-dependent grain size, texture and morphology and the magnitude of the intrinsic and thermal components of the residual stress, a model is proposed that explains the origin of internal stresses of thin polycrystalline films with zone T structures. The model was further extended for the CrN/Cr dual-layer system, where the CrN top layer is epitaxially aligned with the underlying highly (200)-oriented Cr interlayer. It is shown for the first time that both the intrinsic and thermal stress components are thickness-dependent, which is associated with the layer microstructure. [Copyright &y& Elsevier]

X-ray photoelectron spectroscopy (XPS) is one of the main methods for elemental and bonding-state characterization in the near-surface region. Applying it as angle-resolved XPS (ARXPS), it is promising for non-destructive depth profiling in the nanometre-thickness range. The challenges for the application of ARXPS are discussed for the early film growth of Ti and Ta on SiO2 produced by in situ magnetron sputtering. The measurements showed several phase-formation processes at the interfaces, which were used as the basis for the ARXPS data analysis and resulted in different interlayer growth information for Ti and Ta. From a systematic ARXPS data interpretation in combination with simulations, limits of the method are critically discussed. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation was used to study the influence of a relative size of adsorbed and substrate atoms on the stress of growing films. Atoms in the system interact via the Lennard-Jones potential. The simulations were performed at a fixed value of systems temperature. The relative size of deposited atoms was changed in the range from 0.7 to 1.2, relatively to the size of substrate atoms. Proposed modeling allows to explain the behaviour of mean biaxial stress for systems with different sizes of adsorbed atoms and a substrate. For considered systems, significant changes in mean biaxial stress have only first three monolayers. [ABSTRACT FROM AUTHOR]

Abstract: CuInSe2 films were prepared at different deposition temperatures (T D) by successive ionic layer adsorption and reaction method with chelating solutions. Influence of T D on film growth, morphology, crystal structure, and band gap energy was investigated. Results showed that elevation of T D mainly enhanced reaction kinetics and ionic diffusion velocity, resulting in fast growth rate of CuInSe2 films, and maximum 20–30 nm/cycle depended upon T D were acquired. Films with 60 dip-cycles could grow from 180 nm to 1000 nm by elevating T D from 30 °C to 90 °C. Surface roughness of CuInSe2 films was closely related to dip-cycle times and T D. Accelerated growth rate by T D could reduce the dip-cycle times for a required film thickness, which improved quality of film morphology. [Copyright &y& Elsevier]

Abstract: Classical molecular dynamics simulations are used to examine the growth of SrO and TiO2 thin films on SrTiO3 (STO). In particular, the simulations consider the deposition of SrO and TiO2 molecules at incident energies of 0.1, 0.5, and 1.0eV/atom onto the (001) surface of STO. The role of surface termination layer (SrO vs. TiO2) is analyzed. In the case of SrO deposition, smooth, ordered films are produced for all incident energies considered and for both surface terminations. By contrast, in the case of TiO2 deposition, three-dimensional islands are formed under all conditions. These predictions are in good agreement with experimental data. Importantly, the simulations explain why these differing morphologies are produced for SrO and TiO2 deposition. [Copyright &y& Elsevier]

Abstract: Ellipsometry is an optical analytical method based on measuring the change in polarization state of reflected or transmitted polarized light. A major challenge of the method has been the computation of reflecting surface physical parameters of interest from the raw measured data. These methods in common use are plagued by local minima and algorithm performance. The mathematics of the light reflection has long taken advantage of some aspects of Complex Analysis. The authors have used much more of Complex Analysis to treat growing films on homogeneous, isotropic substrates. The work presented here explores this advanced treatment for unknown homogeneous, isotropic substrates and for unknown layered substrates. The results lay the groundwork for a set of solution algorithms which are much more powerful and convenient than existing algorithms. Such algorithms eliminate the multiple solution problems inherent in least squares methods. [Copyright &y& Elsevier]

Abstract: The growth of aluminophosphate AlPO4-5 (AFI structure with one-dimensional parallel and straight channels of 7.3Å in cross section) and cobalt-substituted AlPO4-5 (CoAPO-5) films by hydrothermal treatment is investigated. In situ growth on bare (unmodified) silicon substrates using different growth temperatures, times, and precursor mixture compositions was carried out first and yielded films that exhibited either preferred orientation and poor coverage or good coverage but random orientation. Introducing seeded growth, which involved functionalization and seeding of the substrate with the amorphous fraction of an AlPO4-5-containing powder followed by hydrothermal seed growth, c-oriented, well-intergrown films were obtained with a variety of morphologies depending on the synthesis mixture composition and growth conditions. The effect of two different structure directing agents (SDAs), namely triethylamine and tripropylamine, was also examined. Controlled experiments by systematically varying secondary growth duration were performed in order to find the optimal growth time that yields complete coverage while minimizing the degree of misorientation. Seeded growth using dilute precursor mixtures favors c-out-of-plane growth yielding films with a thickness of several micrometers, while reducing the water/Al2O3 molar ratio and executing secondary growth under the appropriate hydrothermal conditions favored in-plane growth yielding well-intergrown films with sub-micron thickness. SEM, XRD, and UV–vis spectroscopy were used to characterize the synthesized AlPO4-5 and CoAPO-5 films. [Copyright &y& Elsevier]

A three-dimensional molecular dynamics simulation is carried out to study the evolution of grains and stresses during the deposition of atoms on the (100) plane of a fcc regular crystal, using the cubic system with x-y periodic boundary conditions. At the bottom an atomic surface and at the top a reflecting wall are assumed. Atoms in the system interact via the Lennard-Jones potential. During simulation the films grow according to the Volmer-Weber mode and exhibit specific shape of the stress curves. When the film becomes continuous, the stress during the growth possesses a maximum value, but later new grain boundaries are formed. Individual atoms in the grain boundaries generate compressive stress in the films. [ABSTRACT FROM AUTHOR]

Abstract: The non-existence of a strongly bound wetting layer for the system para-hexaphenyl (6P)-KCl(001) was verified by thermal desorption spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS). The 6P films were grown by physical vapour deposition under ultrahigh vacuum conditions at 400 K. TDS showed just a single desorption peak even down to a coverage of 0.1 nm mean film thickness. The heat of evaporation for 6P was determined to 2.3 eV. From the change of the XPS K2p substrate signal as a function of the mean film thickness one can conclude that a strong de-wetting exists at the very beginning of the 6P layer growth at 400 K. Additional investigations with atomic force microscopy reveal that at this initial stage the film grows in a form of needle like islands with a high aspect ratio and subsequently terraced mounds of 6P are formed. No dissociation of 6P on KCl was observed. [Copyright &y& Elsevier]

Abstract: Spray pyrolysis of di-n-butyltin(IV) diacetate (DBTDA) has led to the deposition of [200]-oriented SnO2 film on a glass substrate. In order to clarify growth mechanism of the preferential orientation the sprayed SnO2 thin film has been investigated by using the atomic force microscopy and the X-ray photoelectron spectroscopy. The results have suggested that the sprayed solution forms the SnO2 small particles on the glass substrate and they spread overall relatively soon. At the very early stage each particle grows with almost the same rate and only its density increases with no change in a surface roughness. [Copyright &y& Elsevier]

Based on a modified interaction potential and experimental results, an extensive study of ion-energy-correlative thin film growth is presented, As a result, an analytical model for ion energy dissipation into top surface layers is proposed. The proposed model extends previously published models and includes analytical expressions for lattice damage by atomic displacement in surface and subsurface layers. Theoretical calculation indicated that there were three distinctive ion energy regimes within which the different processes occur to the condensed adatoms. The medium energy region (in tens of eV) is a favorite "energy window" from which the pre-deposited atoms or atomic clusters on the substrate can be stimulated further to be rearranged by absorbing the effective energy from an energetic ion beam, leading to uniform film growth. However, over the energy region, the ion can penetrate deeply into the film, and more damage will be caused in the subsurface layer or bulk in this case, which results in the growth of poor-quality or amorphous films. When the ion energy is lower than the "energy window", there is no driving effect for adatoms in both surface and subsurface layers. The molecular dynamic simulations and experimental results have verified the validity of the proposed analytical model and optimal ion energy regimes. [ABSTRACT FROM AUTHOR]

Abstract: The surface spectroscopic methods, e.g. AES and XPS, are widely used in studies of thin film growth. In experiments spectroscopic data are recorded as intensity–film thickness curves. Much theoretical effort had been devoted to calculation AES intensity–thickness functions for different growth modes. A key element of such calculations is finding coverage in each layer. Recently, we developed two models of thin film growth that allow exact determining of coverage in all layers of a growing film. In island growth model the lateral islands growth occurs via capture of migrating adatoms whereas their vertical growth-owing to direct impingement of deposited atoms. Analysis of arising film morphology yields coverage in each layer in analytic form. In layer growth model based on rate equation approach combined with a feeding zone accounting for interlayer mass transport coverage in successive layers are calculated in a straightforward manner. Thus the AES intensity–film thickness functions were derived analytically for island growth and computed numerically for layer growth in various growth regimes (complete/incomplete condensation) and modes (smooth/rough), enabling experimental data to be examined quantitatively and in greater detail than has previously been reported. [Copyright &y& Elsevier]

Abstract: The growth of polypyrrol layers on gold electrodes in phosphate solutions of pH=6.7 was analyzed using “in situ” voltammetric and ellipsometric techniques. Significant variations in optical indices and thickness were detected as a function of the applied potential and the aging time of storage in phosphate solutions with or without ascorbic acid. More compact layers were grown at 1.4 V vs. RHE than by applying a lower potential. The more compact layers show a slow but progressive increase in thickness or swelling after several hours of storage in the electrolyte. This effect increases when the interface is cathodically polarized. Optical indices and thickness of the layers formed under the different applied potential/time programmes were estimated. [Copyright &y& Elsevier]

The interface reactions between transition metal oxide substrates and ultra thin metal layers of different thickness (<15 nm) have been investigated by using x-ray photoelectron spectroscopy (XPS). To a different extent oxidation of deposited metal and reduction of the oxidic substrate is visible for complementary layer systems. For the interface nickel oxide/manganese an enhanced reaction is found compared to the system manganeseoxide/nickel. Based on the experimental data a model of the evolving interface is proposed. [ABSTRACT FROM AUTHOR]

Abstract: Chemical vapor deposition is widely used in integrated circuit fabrication. With the increasingly stringent requirements for product quality and yield, it is necessary to apply process monitoring, fault detection and eventually closed-loop control to the deposition process. The implementation of these tools requires an in situ sensor that can measure film properties in real time. This paper discusses an extended Kalman filter (EKF) based in situ sensor and its application in chemical vapor deposition of yttria-stabilized zirconia (YSZ) on a silicon substrate. The sensor measures reflectance from the film surface at 950 and 470nm. The measurements were processed by the EKF to estimate film thickness, growth rate and surface roughness. The challenge with estimation of film microstructure like roughness lies in the process dynamic model for microstructure evolution at small scales, which in general is high-dimensional and nonlinear. In this work a simple but adaptive process dynamic model and a detailed optical sensor model were used to study how a simple process model could aid in estimation. Based on these models the observability of the process was discussed. The estimated film properties were verified with ex situ characterization using a scanning electron microscope (SEM) and an atomic force microscope (AFM). Finally sensitivity and robustness of EKF were discussed, along with our perspectives on future work on in situ sensing for thin film deposition. [Copyright &y& Elsevier]

Abstract: RuO2 thin films were grown on (001) LaAlO3 utilizing the pulsed laser deposition technique. Atomic force microscopy was used to check the topography of films at different growth stages. The in situ resistivity measurement was used to monitor the resistance change during and post film growth with changes of resistivity associated with the change of film growth mode. Transmission electron microscopy was used to reveal film quality and crystalline information. The layer-plus-island Stranski–Krastanov growth mode is proposed according to above results. The ambient O2 filled during growth is found to be the main oxygen source for the formed RuO2. [Copyright &y& Elsevier]

Abstract: The influence of thermal annealing on the morphology and structure of nanometer range thickness vanadium oxide films deposited by ALCVD on silicon substrate was investigated by AFM. The appearance of crystalline centres with typical rectangular V2O5 plates was clearly observed from 400°C. Furthermore, spectacular 2D-reorganisation phenomenon with increasing temperature was pointed out since, initial circular particles change to elongated ones with a rectangular shape with increasing temperature. This reorganisation process results from an increase in the high surface atomic mobilities with increasing temperature. The growth of V2O5 particles in the ab-plane occurs preferentially along the b-direction for which the atoms density is higher, in good agreement with results previously deduced from XRD analyses. The latter show limitation of the coherence domains values along the a-axis for temperatures higher than 450°C. [Copyright &y& Elsevier]

Abstract: A new cell-automata model describing the growth process of cluster by an infection probability is introduced and investigated with Monte Carlo method. The multifractal property and the percolation property are included in this model. Analysis on the surface morphology shows interesting multifractal behavior in great agreement with the experiment AFM images, indicating that this model can simulate a series of film dynamic growth. A novel form of percolation-related phase transition other than power law in traditional scaling theory is also showed by introducing a simple grand canonical ensemble partition function . [Copyright &y& Elsevier]

Abstract: Fe is deposited on a single crystal bulk Si (100) and separated by implanted oxygen (SIMOX) substrate by the use of ion beam sputter deposition (IBSD) method to form β-FeSi2 film. Photoluminescence (PL) is measured for these films, after the films on Si substrate are thermally annealed at 1153K for 24h. The PL intensity at around 0.83eV dramatically increased. Such feature has not been seen on SIMOX substrate. To understand how the structural and compositional properties of the film and the substrate affect the PL characteristics, cross-sectional transmission electron microscopy (XTEM) has been applied. The results revealed that these films have quite different structures after thermal annealing due to aggregation of the film. In the bulk Si case, β-FeSi2 has a particle size of about 200nm, whereas on SIMOX, it has particle sizes of about 20–30nm on insulator. Moreover, β-FeSi2/Si interface remains in the former but not in the latter case. It is revealed that these structural properties are important for enhancement of PL intensity. [Copyright &y& Elsevier]

Abstract: Mercury sulfide (HgS) nanocrystalline thin films have been grown onto amorphous glass substrate by successive ionic layer adsorption and reaction (SILAR) trend at room temperature (27°C). The optimized preparative parameters including ion concentration, number of immersion cycles, and pH of the solution are used for fine nanocrystalline film growth. A further study has been made for the structural, surface morphological, optical and electrical properties of the films by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical absorption and dc two point probe method. The as-deposited grown HgS nanocrystalline films exhibited cubic phase, with optical band gap (E g) of 2.0eV and electrical resistivity of the order of 103 Ωcm. SEM and TEM images confirmed films of smooth surface morphology and nanocrystaline in nature with fine crystallites of 20–30nm diameter, respectively. [Copyright &y& Elsevier]

Based on a hexagonal lattice which includes deposition, dissociation, and diffusion, we performed a kinetic Monte Carlo model to explore thin film growth via pulsed laser deposition (PLD) and molecular beam epitaxy (MBE) within the submonolayer regime. First and second nearest-neighbor interactions calculated by the Morse potential are taken into account in this case. These simulations show that thin film deposition by PLD is markedly different from that by MBE. With PLD, as pulse duration decreases, the island density increases and the island size decreases. Similarly, at temperature T = 550 K, the scaling function for MBE is rather similar to that of the analytical prediction for a critical island size of i = 2, while the scaling function for PLD changes from an i = 1 behavior to an i = 0 behavior with the decrease in pulse duration. [ABSTRACT FROM AUTHOR]

The core structure and growth process of stacking-fault tetrahedron (SFT) in Si film growth are investigated, by adopting the Cl-adsorbed Si(111) surfaces and using molecular dynamics (MD) simulation based on empirical interatomic interactions. It was shown that most Cl atoms on the substrate diffuse onto the surface and the defects barely appear. However, when more than one Cl atoms aggregate on the Si(111) substrate, the dome structure of Si atoms covering the Cl atoms is produced and it grows into a stacking-fault tetrahedron. These theoretical results are in agreement with recent observations. [Copyright &y& Elsevier]

The stages of fullerenes-Ni film growth were studied with scanning force microscopy. In the first stage the formation of separated fullerenes grains and Ni nanocrystals were observed. In later stages the interaction between growing objects and agglomeration process of Ni nanocrystals could be noticed. Scanning electron microscopy and transmission electron microscopy were used to obtain information about the structure and morphology of compact forms of the growing film. [Copyright &y& Elsevier]

Ag films with a thickness between 2 nm and 20 nm were analyzed with regard to their sheet resistance. The films were all deposited in one batch, but the Ar pressure, sputtering power as well as the duty cycle were varied between the depositions of the individual samples. The sheet resistance was determined as a function of film thickness. It could be shown that a certain minimum film thickness dec is needed that the films show a measurable conductivity. This minimum film thickness is correlated with the percolation threshold of the Ag films. The coalescence of previously isolated islands leads to a steep increase of the conductivity with increasing film thickness until a fully closed film is formed. The minimum film thickness dec depends especially on the sputtering power and the Ar pressure. An increased Ar pressure leads to an increase of dec from 3.5 nm at 0.35 Pa to 9.2 nm at 7 Pa. For an increasing sputtering power dec is reduced from 4.2 nm at 1.18 W/cm2 to 3.6 nm at 4.74 W/cm2. The model of Mayadas and Shatzkes is used to describe the conductivity in dependence on the film thickness. This model takes into account the influence of the film surfaces as well as the influence of the grain boundaries on the scattering of the electrons. [Copyright &y& Elsevier]

The paper presents the results of average stress measurements during deposition of thin copper and silver films and during ion irradiation of molybdenum thin films. Deposition chamber and ion implanter were equipped with the same optical systems for radius of curvature measurement (scanning technique). The average stress in the 92 nm total thick Cu/Ag/Cu/Ag system on 100 μm Si substrate during deposition at room temperature is reported. Deposition process was intermitted after each material. The non-continuous changes of the stress are interpreted as differences in temperature of the sample in different deposition stages. High residual stresses up to 3 GPa were evidenced in the Mo thin films deposited on Si substrate with RF sputtering. During ion implantation with Kr and Ar ions stress relaxation effect of Mo thin films was observed. Kr ion irradiation of the silicon substrate without a film was additionally performed. After the irradiation (total dose 1.4×1015 ions/cm2), the implanted region of the silicon wafer was under compressive stress. A stress maximum was evidenced for a dose of 1×1014 ions/cm2. [Copyright &y& Elsevier]