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In this work, we used a combination of photoluminescence (PL), high resolution X-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) techniques to investigate material quality and structural properties of MBE-grown InGaAsBi samples (with and without an InGaAs cap layer) with targeted bismuth composition in the 3%–4% range. XRD data showed that the InGaAsBi layers are more homogeneous in the uncapped samples. For the capped samples, the growth of the InGaAs capped layer at higher temperature affects the quality of the InGaAsBi layer and bismuth distribution in the growth direction. Low-temperature PL exhibited multiple emission peaks; the peak energies, widths, and relative intensities were used for comparative analysis of the data in line with the XRD and RBS results. RBS data at a random orientation together with channeled measurements allowed both an estimation of the bismuth composition and analysis of the structural properties. The RBS channeling showed evidence of higher strain due to possible antisite defects in the capped samples grown at a higher temperature. It is also suggested that the growth of the capped layer at high temperature causes deterioration of the bismuth-layer quality. The RBS analysis demonstrated evidence of a reduction of homogeneity of uncapped InGaAsBi layers with increasing bismuth concentration. The uncapped higher bismuth concentration sample showed less defined channeling dips suggesting poorer crystal quality and clustering of bismuth on the sample surface. [ABSTRACT FROM AUTHOR]

A calculation is presented for the direct conversion of a measured luminescence signal to the implied open circuit voltage. The effects of re-absorption, spectral dependence, and interference with front and back interfaces are all included, so long as the optical properties of the structure are known. The method is validated through a comparison of the terminal open-circuit voltage with the photoluminescence intensity of Cu(In,Ga)Se2 solar cells, each as a function of illumination intensity. [ABSTRACT FROM AUTHOR]

CdSeTe/CdMgTe double heterostructures were produced with both n-type and unintentionally doped absorber layers. Measurements of the dependence of photoluminescence intensity on excitation intensity were carried out, as well as measurements of time-resolved photoluminescence decay after an excitation pulse. It was found that decay times under very low photon injection conditions are dominated by a non-radiative Shockley-Read-Hall process described using a recombination center with an asymmetric capture cross section, where the cross section for holes is larger than that for electrons. As a result of the asymmetry, the center effectively extends photoluminescence decay by a hole trapping phenomenon. A reduction in electron capture cross section appeared at doping densities over 1016cm-3. An analysis of the excitation intensity dependence of room temperature photoluminescence revealed a strong relationship with doping concentration. This allows estimates of the carrier concentration to be made through a non-destructive optical method. Iodine was found to be an effective n-type dopant for CdTe, allowing controllable carrier concentrations without an increased rate of non-radiative recombination. [ABSTRACT FROM AUTHOR]

The solar-energy absorption material β-In2S3 was characterized using temperature-dependent photoconductivity (PC) measurements in the temperature range between 30 and 340 K in this study, and thermoreflectance (TR) and photoluminescence (PL) measurements were carried out to identify near-band-edge transitions in the β-In2S3 tetragonal crystal. The experimental analyses of PL, PC, and TR confirmed that β-In2S3 is a direct semiconductor with a band gap of 2.073 eV at 30 K and 1.935 eV at 300 K. The PL and PC spectra manifest some defect-related features in the β-In2S3 single crystal. Two defect emissions and two band-edge luminescences were simultaneously detected in the PL spectrum at 30 K, and the temperature-dependent PC spectra of β-In2S3 from 160 to 300 K reveal an additional defectlike or band-to-band feature with an energy located above the conduction band edge (EC). The temperature dependences of the PC transition features in the β-In2S3 defect crystal were analyzed. The origin and mechanism of all defect states and band-edge transitions in the β-In2S3 single crystal are evaluated and discussed. [ABSTRACT FROM AUTHOR]

Selective enhancement and suppression of the photoluminescence arising from Si0.5Ge0.5/Si multiple quantum wells by photonic crystals (PCs) have been demonstrated. The formation of the stop band in PCs is designed to be a filter as well as a reflector. It is found that the self-assembled PCs are able to selectively enhance the luminescence of the type-II transitions at the interface between Si and Si0.5Ge0.5/Si layers and suppress the emission from Si. Our working principle shown here can be extended to many other material systems and should be very useful for creating high power solid-state emitters. [ABSTRACT FROM AUTHOR]

A new approach is demonstrated for investigating charge and spin diffusion as well as surface and bulk recombination in unpassivated doped semiconductors. This approach consists in using two complementary, conceptually related, techniques, which are time-resolved photoluminescence (TRPL) and spatially resolved microluminescence (μPL) and is applied here to p+ GaAs. Analysis of the sole TRPL signal is limited by the finite risetime. On the other hand, it is shown that joint TRPL and μPL can be used to determine the diffusion constant, the bulk recombination time, and the spin relaxation time. As an illustration, the temperature variation of these quantities is investigated for p+ GaAs. [ABSTRACT FROM AUTHOR]

We have investigated the InGaAs/GaAsSb/InAlGaAs/InAlAs type-II 'W' quantum wells (QWs) grown on InP substrates by molecular beam epitaxy. The photoluminescence (PL) emission wavelength longer than 2.56 μm at room temperature (RT) is demonstrated for the first time in this material system. The PL emission peaks of our designed samples can cover a wide range from 2 to 2.5 μm at cryogenic temperature. The samples show good optical quality that the reduction in integrated PL intensity is only around one order of magnitude from 35 K to RT. We found that the integrated PL intensity decreased as the emission wavelength increased, which is due to the reduction in the electron-hole wave function overlap. This is consistent with the calculated result. In the power dependent PL measurements, the emission peak of 'W' type QWs show blue shifts with the excitation power (Pex) but does not follow the Pex1/3 rule as predicted by type-II band bending model. The localized states filling effect gives reasonable explanations for the observed phenomena. [ABSTRACT FROM AUTHOR]

We present systematic experimental studies of the temperature dependence of continuous wave and time-resolved photoluminescence spectroscopy in self-assembled InAs/GaAs nanostructures as the shape of quantum structures evolved from dot to ring. The carrier dynamics show strong dependence on the geometrical shape of the nanostructures under investigation. An increase in photoluminescence decay time of the excited and ground states is observed as the shape of nanostructures changed from dot, volcano, to ring. It is attributed to the carrier thermalization between the dark and ground states. The photoluminescence excitation spectra of the quantum rings reveal resonances related to the dark states. A rate equation model is proposed to interpret the observed carrier dynamics. [ABSTRACT FROM AUTHOR]

Te-doped and ZnTe-doped diluted ZnSeTe samples were grown by using metal-organic chemical vapor deposition. The green lights emitted from these two samples in the photoluminescence (PL) measurement have different peak emission energies and can be attributed to different emission mechanisms. For the Te-doped sample, the PL emission band is excitation laser power independent, the lifetime of the PL emission is short, and the PL emission could be attributed to the emission originated from Te isoelectronic centers. For the ZnTe-doped sample, the energy of the green emission band is laser power dependent, the PL lifetime is much longer than the Te-doped sample, and the PL emission could be attributed to the emission from type-II ZnTe/ZnSe quantum dots. The results demonstrate that there are two different mechanisms responsible for the green PL emission in ZnSeTe system and our growth methods provide a way of selecting one of the two mechanisms for the green light emission in this system. [ABSTRACT FROM AUTHOR]

X-ray absorption near-edge structure (XANES) and x-ray emission spectroscopy (XES) measurements were used to investigate the effect of Mg doping in ZnO nanorods. The intensities of the features in the O K-edge XANES spectra of Zn1-xMgxO nanorods are lower than those of pure ZnO nanorods, suggesting that Mg doping increases the negative effective charge of O ions. XES and XANES spectra of O 2p states indicate that Mg doping raises (lowers) the conduction-band-minimum (valence-band-maximum) and increases the band gap. The band gap is found to increase linearly with the Mg content, as revealed by photoluminescence and combined XANES and XES measurements. [ABSTRACT FROM AUTHOR]

Surface photovoltage (SPV) and photoluminescence excitation (PLE) spectroscopy have been used to characterize multiple stacked self-assembled InAs quantum dot (QD) structures with and without InGaAs overgrown layers. The SPV spectra contain rich optical features that originate from every relevant portion of the samples, including the QDs, wetting layer (WL), hybrid quantum well (HQW), and GaAs barrier. The excited state peak positions detected by PLE coincide with those from SPV measurements, which indicates that the QD ensembles are of monomodal distribution. The redshifts of the QD transitions have been attributed to the altered strain distribution, and the reduction in the linewidth of the WL signals indicates a partial alleviation of the surface roughness effect by the incorporation of InGaAs overgrown layers. An additional spectral feature situated between the highest lying QD state and the WL signals has been attributed to the electronic transition in the InAs/InGaAs dots-in-well structure. [ABSTRACT FROM AUTHOR]

This work presents the deep-level photoluminescence of coherently strained GaAsN/GaAs quantum-well (QW) structures with various GaAsN thicknesses and N contents. A broad deep-level emission at ∼1.1 eV is observed, whose wavelength is redshifted as the GaAsN thickness increases. Based on its energy separation from the QW emission, this emission is attributed to a transition between the QW electron ground state and a deep level at ∼0.2 eV above the GaAsN valence-band (VB) edge. This level is shown to be tied to the GaAs band edge. A transition between this level and the GaAs conduction band allows the GaAsN–GaAs band alignment to be evaluated. A type II band lineup is obtained with VB offsets of 0.03 and 0.002 eV for N=0.6% and 1.8%, respectively. The decreased VB offset suggests a transition from type II to type I with increasing N content. Thermal annealing effectively removes this level and improves the QW emission. The concentration of this level is not clearly correlated with N content, suggesting that this level is induced by a low-temperature growth of the GaAsN layer to suppress the composition fluctuation. Given its energy, this level is tentatively assigned to VGa. [ABSTRACT FROM AUTHOR]

InGaN quantum dots (QDs) deposited on SiNx nanomasks have been investigated by atomic force microscopy, photoluminescence (PL), and photoluminescence excitation (PLE) measurements. It was found that the size of QDs can be well controlled by SiNx nanomasks, enabling the manipulation of quantum confinement effect. The PL spectra of InGaN QDs contain several fine structures, and the main peaks can be attributed to families of QDs with different sizes. The emission arising from InGaN QDs and GaN buffer layer can be clearly distinguished based on PLE measurement, which can be used to improve the interpretation in the previous reports. Our study indicates that the quantum confined Stark effect due to piezoelectric field plays a very important role in the optical properties of InGaN QDs, which is very useful for the application of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Raman and photoluminescence spectra of cubic Zn1-xCdxSe (0≦x≦0.32) epilayers were obtained at high pressure. The impurity mode I observed in the phonon Raman spectra at low temperature confirms the intermediate phonon mode behavior. A split transverse optical phonon mode was found in the down-stroke high-pressure Raman scattering. Additionally, the pressure-dependent longitudinal optical (LO) phonon frequencies and the Grüneisen parameter (γLO) were obtained by quadratic polynomial fitting. Pressure-driven resonant Raman scattering effect was observed in samples with a high Cd concentration (x≧0.18). The critical pressure of semiconductor-to-metal phase transition (Pt) decreases as the Cd content increases. As the Cd concentration increases from 0 to 0.32, Pt falls from 13.6 to 9.4 GPa, according to Pt (GPa)=13.6-6.8x-20.3x2. [ABSTRACT FROM AUTHOR]

Ion channeling technique using MeV C++ ions was used to study strain in self-assembled InAs quantum dots (QDs) buried in GaAs matrix. Because of the use of heavy ions, we were able to observe an angular shift in the angular scan of the In signal relative to that of the Ga/As signal. This provided a direct evidence that the InAs lattice is larger than that of GaAs in the growth direction. Combining the channeling results in [100] and [110] directions and the photoluminescence emission spectrum, we conclude that the InAs QDs are under tensile strain in the growth direction and have the same lattice constant as that of GaAs in the lateral direction. Thermal annealing causes the strain to relax, first in the growth direction and then in the lateral direction as the annealing temperature increases. The photoluminescence spectra of the QDs before and after annealing indicate, however, that composition intermixing also takes place during annealing and is the dominant factor in determining the band gap energy of the QDs. [ABSTRACT FROM AUTHOR]

Multilayer self-assembled InAs/GaAs quantum dot (QD) structures with varying GaAs spacer layer (SL) thickness are systematically investigated using surface photovoltage spectroscopy (SPS) and photoluminescence (PL). The optical transitions are more clearly visible in the room-temperature SPS spectra and exhibit more features in comparison to PL. The enhanced electronic coupling effect for thinner SL results in the appearance of an additional excited state lying higher than the second excited quantum dot state. A peculiar feature denoted as QDX below the fundamental transition is tentatively attributed to the optical absorption from uncoupled dots of which the density is lower than that of vertically coupled ones. The transition blueshifted with a decrease of the SL thickness indicates that the materials intermixing between InAs QDs and GaAs SL are strongly driven by strain. The intensity ratio between the ground state and QDX in the temperature dependent PL spectra is found to be associated with the processes of enhanced thermal carrier transfer between QDs and tunneling of carriers between QDs in adjacent layers for a stack due to a reduction in SL thickness. The results demonstrate considerable diagnostic value of SPS for the nondestructive characterization of vertically coupled self-assembled QD structures. [ABSTRACT FROM AUTHOR]

We report investigations on the optical properties of type-II CdTe/CdSe core-shell quantum dots. By varying the core size, we provide an elegant way to verify that the detected emission signal indeed arises from type-II band alignment. The photoluminescence (PL) peak energy increases with a third root of the excitation power. Both of the PL peak energy and linewidth exhibit unique temperature dependence. All these observations can be rationalized by the band bending effect resulting from the spatially separated photoexcited carriers in a type-II band alignment. [ABSTRACT FROM AUTHOR]

Several approaches have been employed to grow high-quality ZnSe epilayers on Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrates. The ZnSe epilayers were characterized by photoluminescence spectroscopy. Migration enhanced epitaxy and inserting an in situ thermal annealing ZnSe buffer layer effectively reduced the intensity of deep level emissions from the ZnSe epilayer grown on a 6°-tilted Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrate. Optimized conditions for growing high-quality ZnSe were used to deposit ZnCdSe/ZnSe multiple quantum wells on Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrates. Photoluminescence spectroscopy revealed quantum-confinement effect in the ZnCdSe multiple quantum wells. The evolution of the exciton emission peak energy and the linewidth as a function of temperature indicate a low density of localized sites in the sample with a well width of 1 nm. In the high-temperature regime, the thermal quenching of the excitonic emission intensity from ZnCdSe quantum well structures was governed by the thermal activation of carriers from quantum-well-confined states into barrier states. [ABSTRACT FROM AUTHOR]

Magnesium-doped, p-type GaN containing H was irradiated with MeV protons at room temperature and then annealed at a succession of increasing temperatures, with the behavior of defects and H in the material being followed through infrared absorption spectroscopy, nuclear-reaction analysis of the H, and photoluminescence. The results support the annihilation of Ga Frenkel pairs near room temperature, leaving the N interstitial and N vacancy to influence the elevated-temperature behavior. Multiple changes are observed with increasing temperature, ending with thermal release of the H above 700 °C. These effects are interpreted in terms of a succession of complexes involving Mg, the point defects, and H. [ABSTRACT FROM AUTHOR]

Temperature-dependent photoluminescence measurements and deep level transient spectroscopy have been made to identify defects and deep level traps in InGaAsN alloys lattice-matched to GaAs. The epitaxial layers were grown by molecular beam epitaxy at different substrate temperatures. Defect levels responsible for the quenching of luminescence with increase of temperature have been identified. Several electron trap levels have been identified and characterized in the alloys. The concentrations of all of these increase with N content in the alloy. A dominant center, with an activation energy of ET=0.44 eV, is present in all the samples and its concentration is inversely proportional to photoluminescence intensity. H2O and O present in the source nitrogen are believed to be responsible for the presence of this trap, which also has characteristics similar to the E3 and E4 levels in molecular beam epitaxial GaAs. [ABSTRACT FROM AUTHOR]

Described herein is the incorporation of nanocrystalline silicon nc-Si from porous silicon (PSi) in a silica matrix fabricated by the sol-gel technique that yields highly photoluminescent (PL) and optically transparent monoliths with uniformly distributed nc-Si inclusions or nanoclusters. The sample monoliths were prepared with PSi-derived nanoclusters (PSi-n) with average diameters of 14–45 nm. Concentrated samples of PSi-n-exhibited blueshifted orange emission bands with maximum peaks between 600 and 750 nm with PL emission intensities ten times stronger than those of the original PSi, while diluted samples exhibited UV to blue (350–450 nm) emission bands. The PL quantum yield of the typical PSi-n monoliths was 44% higher than the native PSi. Light absorption measurements showed a linear response to laser powers before the saturation threshold at 80 mW. PL bleaching following 3 h of constant laser power exposure resulted in 90% reduction of the maximum initial PL. Mechanical and thermal stability properties of nc-Si were greatly improved within the silica matrix, demonstrating that PSi-n monoliths’ are more manageable materials that enable the fabrication of samples with high densities of nc-Si for semiconducting and optoelectronic purposes. No special chemical passivation of the nc-Si surfaces was used in the preparation of the PSi-n monoliths. A strong relation between the optical properties of this nanophase material and the size distribution and concentration of nc-Si in the sample is demonstrated. [ABSTRACT FROM AUTHOR]

We report a detailed investigation on the optical transitions of strained type II GaAs[SUB0.7]Sb[SUB0.3]/GaAs (100) multiple quantum wells. For the theoretical calculations, both of the elastic deformational potential of intrinsic compressive biaxial strain, and quantum confinement effects are included. The asymmetric photoluminescence spectra reveal the features of excited state transition and quantum confinement Stark effect at high and low temperatures, respectively. The asymmetry features have also been investigated and confirmed by low-temperature photoluminescence experiments under different excitation power. From polarized photoluminescence excitation and photoconductivity spectra, both of the type I and type II optical transitions can also be clearly identified. [ABSTRACT FROM AUTHOR]

The temperature-dependent behavior of excitonic photoluminescence observed in ZnO/MgZnO multiple quantum wells (MQWs) in the temperature range of 5-300 K is described. In a ZnO/Mg[SUB0.27]Zn[SUB0.73]O MQW grown by laser molecular-beam epitaxy, the luminescence was dominated by localized exciton (LE) emission throughout the whole temperature range studied. Luminescence of free excitons (FEs) was not observed. A simple rate equation is used to describe the quenching of LE emission. The activation energy for LE luminescence quenching is of the order of the localization energy of excitons, suggesting that the thermionic emission of the LEs out of the localization potentials leads to nonradiative recombination. In a ZnO/Mg[SUB0.12]Zn[SUB0.88]O MQW having lower barriers, the luminescence was dominated by LE emissions at low temperatures, while the FE transition was dominating emissions at temperatures above 175 K. A rate equation assuming one nonradiative recombination channel is used to describe the quenching of the transitions observed. The activation energy for LE luminescence quenching deduced in this sample is also of the order of the localization energy of excitons. The temperature dependences of FE emission intensities are also discussed by using a simple rate equation in which a thermal release effect of LEs toward FEs is taken into account. [ABSTRACT FROM AUTHOR]

We present studies of the compositional dependence of the optical properties of AlGaN(0 GaN. As aluminum concentration increases, the color of the band changes from yellow (2.2 eV) to blue (2.6 eV). The shift was less than that of the band gap. Together with previously published studies, it implies that the deep acceptor level is pinned to a common reference level to both materials, thus the deep level responsible for the yellow emission is used as a common reference level to determine the band alignment in AlGaN heterojunctions. Combining with the near-band-edge modulation spectra, the estimated ratio of conduction-to-valence band discontinuity is 65:35. Our results are close to the values obtained from PL measurements on AlGaN/GaN quantum wells and those calculated by linear muffin-tin orbital method and linearized augmented plane wave method. c 2001 American Institute of Physics. [DOI: 10.1063/1.1383259]. [ABSTRACT FROM AUTHOR]

Deep-level defect-related optical properties of undoped n-type GaN grown by metalorganic chemical vapor deposition are investigated using photoluminescence (PL), optical absorption (OA), photoconductivity (PC), and persistent photoconductivity (PPC) measurements. From the temperature dependence of the PL and OA, we find that the yellow luminescence (YL) is due to shallow-to-deep donor recombination. PL, PC, and PPC results manifest a strong correlation in properties related to deep levels. Samples which emit YL exhibit a PC peak at 1.9 eV due to the photoionization of deep levels as well as to the persistent photoconductivity effect, whereas samples with no YL have no PC peak in the forbidden gap and no PPC at any photon energy, suggesting a common origin. Furthermore, two types of PPC behavior were observed depending on the sample quality: typical stretched exponential decay in relatively thick samples and photocurrent quenching and a subsequent reduction of the dark current in thin samples. An explanation of the latter phenomenon based on photoinduced metastable electron traps in a highly defective layer near the interface is suggested from the temporal behavior of the PC. These traps seem to disappear slowly after the illuminating light is turned off. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

High resolution measurements of spectrally resolved cathodoluminescence (CL) decay have been made in several commercial and experimental phosphors doped with Eu and Tb at beam energies ranging from 0.8 to 4 keV. CL emission from the lowest two excited states of both rare-earth activators was compared to the decay of photoluminescence (PL) after pulsed laser excitation. We find that, at long times after the cessation of electron excitation, the CL decay rates are comparable to those measured in PL; at short times, the decay process is considerably faster and has a noticeable dependence on the energy of the electron beam. These beam energy effects are largest for the higher excited states and for phosphors with larger activator concentrations. Measurements of the experimental phosphors over a range of activator fractions from 0.1 to 0.002 show that the beam energy dependence of the steady-state CL efficiency is larger for higher excited states and weakens as the activator concentration is reduced; the latter effect is strongest for Y[sub 2]SiO[sub 5]:Tb, but also quite evident in Y[sub 2]O[sub 3]:Eu. We suggest that the electron beam dependence of both the decay lifetimes and the steady state CL efficiency may be due to interaction of nearby excited states which occurs as a result of the large energy deposition rate for low energy electrons. This picture for nonradiative quenching of rare-earth emission is an excited state analog of the well-known (ground state-excited state) concentration quenching mechanism. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents the results of photoluminescence investigation of gallium nitride (GaN) films grown by metalorganic chemical vapor deposition on (100) gallium arsenide. Introduction to GaN; GaN growth and characterization; Experimental results and analysis of photoluminescence characteristics.

Presents information on a study which explored the mechanisms behind green photoluminescence in zinc oxide phosphor powders. Experimental procedure; Results and discussion; Conclusion.

Presents a study that investigated photoluminescence in strained gallium antimony/indium gallium antimony quantum wells by metalorganic chemical vapor deposition. Details of the experiment; Results and discussion; Conclusion.

Structural and optical properties of Mg-doped AlGaN/GaN superlattices have been investigated by photoluminescence, scanning electron microscopy, cathodoluminescence (CL), and transmission electron microscopy (TEM). We found that the edge blue-band emission shows a strong optical anisotropy. Through the combination of the CL and TEM images, we clearly establish that the underlying microstructure responsible for the blue luminescence in Mg-doped AlGaN/GaN arises from the pyramidal defects. The observed optical anisotropy is due to the well aligned pyramidal structure. Our result provides one of the model systems to demonstrate the correlation between optical transition and structural defect in a solid. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) properties of ZnO films grown epitaxially on lattice-matched ScAlMgO[sub 4] substrates are investigated. PL spectra of ZnO layers measured at 5 K are dominated by neutral-acceptor bound exciton emission at 3.359 eV (I[sub 6]) with a linewidth of 0.8 meV. Free exciton emission develops as temperature is raised and eventually dominates at temperatures higher than 120 K. Temperature dependence of intensity of the free exciton emission is discussed. [ABSTRACT FROM AUTHOR]

Erbium (III) oxide nanocrystals prepared using the inverse microemulsion technique were dispersed in sol-gel TiO[sub 2]/γ-glycidoxypropyltrimethoxysilane (GLYMO) composite thin films at low temperature. X-ray diffraction analysis and transmission electron microscopy observation show that the erbium (III) oxide nanoparticles have a nanocrystalline structure and their size is in the range from 5 to 30 nm. A relatively strong room-temperature photoluminescence (PL) was observed at 1.531 μm with a full width at half-maximum (FWHM) of 22 nm. The shape, peak position, and FWHM of the PL curve from the composite thin films are quite comparable to those prepared by other methods. The PL peak of the composite thin film reached a maximum intensity after a heat treatment at 300 °C. Fourier transform infrared results show that water and hydroxyl groups are present in the films and are responsible for the luminescence peak intensity reduction of the films heated at higher temperature. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]