In-plane Grazing Incidence X-ray Diffraction Research Articles

Linear and nonlinear optical response dependency on the crystallite size of CdTe and its structural properties

Cadmium telluride QD thin films of thickness (10→57 nm) has been successfully synthesized using inert gas condensation. The structure of thin films was examined by grazing incident in-plane X-ray diffraction (GIIXD), revealing a hexagonal polymorph structure. A strong confinement regime was achieved where the attained radius (from ~2.6 to 6 nm) of particle size of thin films was smaller than the Bohr radius of their bulk CdTe (~7.3 nm). Linear and nonlinear optical properties were affected by changing the particle size. The optical gap is higher than that of bulk CdTe, it increased from 2.44 to 2.8 eV as film thickness decreased from 57 to 10 nm. All optical parameters such as dispersion parameters (Eso and Ed), oscillator strength (f), lattice dielectric constant (εL), static dielectric constant (εo) and refractive index (no) were increased with film thickness. Likewise, the linear and nonlinear susceptibility (X(1), X(3)) besides nonlinear refractive index (n2) increased with film thickness.

Domain structure transition in compressively strained (100)/(001) epitaxial tetragonal PZT film

A 30-nm-thick epitaxial tetragonal (100)/(001) Pb(Zr0.22Ti0.78)O3 (PZT) thin film was grown at 600 °C on (001) KTaO3 (KTO) single-crystal substrate by metalorganic chemical vapor deposition. The a/c domain structure in the PZT film was analyzed in detail at room temperature by synchrotron x-ray diffraction (XRD) and piezoresponse force microscopy techniques. The temperature dependence of the crystal structure was investigated by XRD reciprocal space mapping and in-plane grazing incidence XRD. The PZT films were grown on KTO substrates under compressive strains from 700 °C to room temperature. This compressive strain gave rise to a perfect (001) orientation below a Curie temperature (TC) of ∼520 °C. An in-plane a-axis lattice parameter for the c domain kept the same value as that of the substrate lattice up to 350 °C despite the ferroelectric transition. Nucleation of the a domain started at around 350 °C. The formation of the a domain released the strain for the in-plane a-axis lattice parameter, as confirmed by in-plane analysis of the crystal structure. The results revealed that the in-plane average surface area of the PZT unit cell continued to match that of the KTaO3 substrate from 700 °C to room temperature, regardless of the domain structure evolution.

Tin telluride quantum dot thin films: Size dependent structural, optical and electrical properties

In the current study, efforts have been made to acquire tin telluride quantum dot (QD) thin films that work at room temperature and in the region of visible and near-infrared (NIR). SnTe ingot and thin films were formed using the solid solution and inert gas condensation (IGC) techniques respectively. A cubic polymorph structure was identified using XRD for the prepared SnTe ingot, while grazing incident in-plane X-ray diffraction (GIIXD) and HR-TEM electron diffraction was used for identifying the thin films. The average particle size was found to increase from 2.3 to 9.6 nm with increasing film thickness from 5 to 25 nm. The optical gap of thin film QDs is wider than those of bulk samples; this is attributable to the quantum confinement effect. As a result of quantum confinement, SnTe thin films have optical gap values in the visible and NIR region (2–0.85 eV) instead of being in the infrared region (0.19 eV) of their bulk materials counterpart. The electronic transition was described by studying various important optical parameters such as optical conductivity (σop), interband transition strength (JCV), and surface and volume energy loss functions (SELF, VELF). Electrical conductivity shows a degenerate semiconductor performance. I–V characteristic show symmetric nonlinear behavior for 10 and 15 nm film thickness.

Impact of calcination temperature on the structure, optical and photoluminescence properties of NanocrystallineCerium oxide thin films

Nanocrystalline cerium oxide films were effectively synthesized on glass substrates via hydrothermal and dip coating techniques at various calcination temperatures (CT) from 300 to 550 °C. Impact of CT on the structure, surface morphology, optical and photoluminescence (PL) properties of cerium oxide (CeOx) films has been investigated. The grazing incident in-plane X-ray diffraction (GIIXD) analysis revealed that thin films acquire cubic fluorite nanostructure of CeO2, with average crystallite size in the range of 3.77–7.63 nm for films of different CT. XPS results revealed the existence of amorphous Ce2O3 in nanostructure CeOx films with crystalline CeO2 phase that was identified by GIIXD results. AFM images manifestations of CeOx thin film at various temperatures with tinny nanoparticles which agglomerate as spherical grains appear randomly distributed with surface roughness ranging from 0.42 to 0.488 μm for films of different CT. Optical properties indicated a narrowing in direct and indirect band gaps of nanocrystalline films than bulk CeO2 to show some fluctuation with the influence of CT that affected with lowering in Ce3+/Ce4+ ratio. Other optical parameters were analysed with the influence of calcination temperatures CT. Photoluminescence (PL) studies indicate the presence of most intense PL emission peak appears at 419 nm revealed the fundamental transition of direct band gap of CeO2, in addition to some other PL emission peaks in the visible range attributed to structural and oxygen vacancies defects states among Ce4f and O 2p bands.

Coherent-strained superconducting BaPb1−xBixO3 thin films by interface engineering

The bismuthate superconductor $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ and its bismuthate heterostructure have gained much attention due to their potential applications, such as topologically protected quantum devices. To fabricate $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$-based junctions or devices with atomically sharp interfaces, researchers have long searched for innovative methods to achieve coherent-strained superconducting $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ films. However, the large lattice mismatches between $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ and widely used perovskite substrates have been huge obstacles hindering the achievement of coherent-strained superconducting films. Here, we successfully fabricated coherent-strained superconducting $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ films on $\mathrm{SrTi}{\mathrm{O}}_{3}$ substrates by inserting $\mathrm{BaCe}{\mathrm{O}}_{3}/\mathrm{BaZr}{\mathrm{O}}_{3}$ buffer layers. By performing both grazing-incidence in-plane x-ray diffraction and transmission electron microscopy, we demonstrated that without buffer layers the $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ films exhibited fully relaxed structures with a reconstructed interface layer. With buffer layers, the superconducting transition temperatures of coherent-strained $\mathrm{BaP}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{B}{\mathrm{i}}_{x}{\mathrm{O}}_{3}$ films were higher than that of relaxed films. Based on these interface-engineering results, this paper provides opportunities for exploring the emergent properties of bismuthate-based superconducting devices, such as quantum computing circuits.

Influence of Film Thickness and Heat Treatment on the Physical Properties of Mn Doped Sb2Se3 Nanocrystalline Thin Films

Nanocrystalline thin films of Sb37.07Mn1.95Se60.98 with different thickness (7, 20, 40, and 80 nm) were successfully prepared via inert gas condensation technique. As-deposited films showed amorphous structure by grazing incident in-plane X-ray diffraction (GIIXD) technique. All films of different thicknesses were heat treated at 433 K for 90 min. The GIIXD pattern of annealed films showed nanocrystalline orthorhombic structure. The effect of thickness of annealed films on the structure and optical properties was studied. Calculated particle sizes are 20.67 and 24.15 for 40 and 80 nm thickness of heat treated film. High resolution transmission electron microscope HRTEM images and their diffraction patterns proved that 40 nm film thickness annealed at different temperature has nanocrystalline nature with observed (high) crystallinity that increases with annealing temperature. Blue shift of optical energy gap was observed from 1.68 to 2 eV with decreasing film thickness from 80 to 7 nm. Film thickness of 40 nm was exposed to different heat treated temperatures from 353 to 473 K to detect its effect on structure and optical and electrical properties. Blue shift from 1.73 to 1.9 eV was observed in its optical band gap due to direct transition as heat treatment temperature decreasing from 473 to 353 K. Electrical conductivity was studied for different heat treated films of thickness 40 nm, and intrinsic conduction mechanism is dominant. The activation energy Ea was affected by heat treatment process.

The correlation of γ-irradiation, particle size and their effects on physical properties of AgInSe2 nanostructure thin films

In this work the effect of γ-irradiation on the optical and electrical properties of near stoichiometric AgInSe2 nanostructure thin films have been characterized. The XRD pattern of ingot AgInSe2 powder prepared by solid state reaction showed tetragonal polycrystalline single-phase structure. The thin films of thickness 75nm were prepared by inert gas condensation (IGC) technique at using constant Ar flow and substrate temperature of 300K.Thin films were exposed to annealing process at 473K for 2h in vacuum of 10−2Torr. The amorphous and tetragonal nanocrystalline structures were detected for as-deposited and annealed films respectively by grazing incident in-plane X-ray diffraction (GIIXD) technique. The structure and average particle size of annealed irradiated films by different γ-doses from 0 to 4Mrad were determined using high resolution transmission electron microscope (HRTEM). Optical transmission, reflection and absorption spectra were studied for both annealed unirradiated and irradiated films. Two optical transitions for each annealed unirradiated and film exposed to γ-irradiation doses from 0 to 4Mrad were observed. The evaluated Eg1 due to 1st transition have decreased from 1.52 to 1.44eV and Eg2 due to 2nd transition have decreased from 2.83 to 2.30eV as the particle size increased from 7.3 to 9.5nm by raising the irradiation dose up to 1Mrad. The behavior of d.c. electrical conductivity with temperature that measured under vacuum was examined for all films under investigation. The evaluated activation energies due to irradiation doses are ranging from 0.58 to 0.68eV.

Higher-K Formation in Atomic Layer Deposited Hf1-XAlxOy

As Si metal oxide semiconducting field effect transistors have continued to scale, SiO2-based gate dielectric and polySi gates have been successfully replaced by high-k dielectrics and metal gate at the 45nm technology node and beyond. In order to continue scaling, improvements of key film properties of the high-k dielectric, such as k-value and leakage current, are needed. The electrical properties of HfO2-based dielectrics may be enhanced by structural modifications, since the k-value is dependent on the crystalline phase (monoclinic k=16, tetragonal k=70 and cubic =29) [1]. HfO2 films typically crystallize into the monoclinic phase, which is its most thermodynamically stable phase [2,3]. Alloying HfO2 with other oxides such as ZrO2, TiO2, Al2O3offer a viable option towards engineering the crystalline phase.In this regards, we have deposited 40 cycles of Hf1-xAlxOy films by atomic layer deposition with Al/(Hf+Al)% ranging from 0 to 25%. A set of samples were annealed under N2 at temperatures ranging from 680 oC to 800oC and compared to the as deposited samples. To investigate the crystallinity of the films, we performed grazing incidence in-plane X-ray diffraction (GIIXRD) on the annealed films and in-situ XRD during an anneal process using synchrotron radiation was used to determine the crystallization temperature (Tc) for the unannealed films. The GIIXRD measurements revealed the presence of non-monoclinic peaks which was also confirmed by the in-situ anneal XRD measurements. The crystallization temperature of the non-monoclinic phase obtained from the in-situ anneal XRD is plotted in Fig.1, where it is shown that higher Al/(Hf+Al)% results in higher Tc. In order to resolve the non-monoclinic phase, extended X-ray absorption fine structure (EXAFS) at was utilized. The EXAFS measurement combined with GIIXRD showed the ALD Hf1-xAlxOy films crystallize into a mixture of the tetragonal and monoclinic phases. The electrical properties were investigated by MOS capacitors with ALD TiN as the metal gate. The electrical measurements show a reduction in EOT after post deposition anneal (PDA). In addition, the leakage current was also reduced by a factor of 10 while maintaining a flat-band voltage that is comparable to PDA HfO2 films under identical conditions. The C-V plots of the as deposited samples and annealed samples are shown in Fig. 2 and Fig.3 respectively. We also investigated the effect of different thermal budgets on the Hf1-xAlxOy films. A ~2Å EOT reduction with lower gate leakage was obtained for devices with post deposition anneal near the crystallization temperature of the Hf1-xAlxOyfilms. However, the electrical performance is degraded for devices with higher or lower post deposition anneal temperature than the films’ crystallization.In summary, we have successfully deposited ALD Hf1-xAlxOy. The crystal phase was confirmed to be a mixed phase of tetragonal with monoclinic. The data shows an enhancement in electrical properties near the crystallization temperature of the Hf1-xAlxOyfilms. Acknowledgements Diffraction measurements were carried out at NSLS (X20A and X20C), BNL, which is supported by the DOE, Division of Materials Sciences and Division of Chemical Sciences, under Contract No. DE-AC02-98CH10886.

Characterization of Pb24Te76 quantum dot thin film synthesized by inert gas condensation

Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3×10−3Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8±0.3nm and 7.2±0.3nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8±0.3nm after heat-treated for 5h at 473K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71eV for the as deposited film to 1.62eV for film heat-treated (5h at 473K). The dc electrical conductivity is increased with raising temperature in the range (303–473K) for all thin films under investigation. The deduced activation energy decreased from 0.222eV for as deposited sample to 0.125eV after heat-treated at 473K for 5h.

Structural and optical properties of PbSe nanostructure thin films prepared by inert gas condensation

Lead Selenide (PbSe) nanostructure thin films synthesized via inert gas condensation (IGC) technique. The structure of as-prepared PbSe nanostructure thin films, were studied using Grazing incident in-plane X-ray diffraction (GIIXD). The study reveals that all films crystallized in cubic structure. The particle size (Ps) of the films, were calculated from X-ray diffraction to be ~5, 8 and 11nm for film thicknesses 20, 46 and 87nm respectively which have been confirmed with those determined from transmission electron microscope (TEM) micrographs. The optical energy gap was found to be increases from 2.22eV to 2.37eV as particle size decreases from 11nm to 5.5nm. In addition, the band tail width increased with decreasing the particle size but the refractive index increases with increasing the particle size of the prepared films.

Effects of temperature on the polymorphism of α,ω-dioctylterthiophene in thin films

Polymorphism of α,ω-dioctylterthiophene (DOTT) thin films (less than 100nm-thick) deposited onto standard silicon substrates is investigated by combining specular and in-plane grazing incidence X-ray diffraction measurements. Two crystal phases are revealed: the bulk phase (b) and the surface-induced phase (s). Previous results showed that s-phase was the most favored close to the substrate surface while b-phase is predominant at the DOTT-air interface. We show here that the relative proportion of these polymorphs is related to sample preparation. Indeed, the preferential crystallization of one phase or the other can be tuned as a function of substrate temperature during film deposition, s-phase being mainly present at high substrate temperature while b-phase is most observed at low substrate temperature. Particularly noteworthy is that thin films exhibiting only b-phase or only s-phase can be obtained according to sample preparation. Furthermore, when samples are annealed above the melting temperature (smectic G phase), the polymorph observed after cooling back to room temperature depends upon the cooling rate, s-phase being predominant at high cooling rate while it is rather b-phase for slow cooling. This behavior is independent of the crystalline phase that was present at room temperature before annealing.

Synthesis and characterization of low particle size nanocrystalline SnSe thin films

Tin selenide (SnSe) nanocrystalline thin films of different thickness from 15 to 70 nm were prepared by inert gas condensation technique. Argon gas flow and substrate temperature were kept constant during deposition process at 2 × 10−3 Torr and 27 °C respectively. Polycrystalline orthorhombic phase structured was deduced for the prepared SnSe ingot powder by X-ray diffraction pattern. The grazing incident in-plane X-ray diffraction (GIIXD) pattern showed nanocrystalline orthorhombic structure for deposited SnSe thin film. The TEM micrographs showed that thin films were nanocrystalline with particle size in the range from 2 to 5.7 nm. The optical band gap Eg of the thin films due to direct allowed transition have values ranging from 2.5 to 2.13 eV as the particle size increases from 2 to 5.7 nm. The photoconductivity spectra of the nanostructured SnSe thin films of different particle size showed transitions at 2.45, 2.34 and 2.21 eV for films of different particle size.

Orientation control of textured SrTiO3 thin films on platinized α-Al2O3 (0 0 0 1) by an ion beam sputter deposition method

SrTiO3 (STO) thin films were grown on Pt/Al2O3 substrates without a Ti adhesion layer by an ion beam sputter deposition method in a range of growth temperatures between 600 and 750 °C. The effect of growth temperature on the film orientation was investigated by high-resolution x-ray diffraction, pole figure measurements and in-plane grazing incidence x-ray diffraction. The film orientation showed a strong dependence on the growth temperature. The films exhibited a predominant (1 1 0) orientation at a low growth temperature of 600 °C. With an increase in growth temperature to 750 °C, a highly (1 1 1)-textured STO film with two different orientation variants was achieved on the Pt/Al2O3 substrate. A narrow full-width at half-maximum of 0.12° for the rocking curve measured on 2 2 2STO reflection and a six-fold symmetry from {1 0 0}STO and {1 1 0}STO pole figures were observed. Three-dimensional island growth mode was observed on the surfaces of all films, as investigated with an atomic force microscope. The evolution of grain shape and size was apparently found with an increase in growth temperature. The root-mean-square roughness of the STO film grown at 750 °C was raised to be about 4 nm due to the surface faceting of (1 1 1)-oriented grains. The growth mechanism of the (1 1 0)- and (1 1 1)-textured STO films on the Pt/Al2O3 substrates was also explained and discussed in detail.

A study on electric properties for pulse laser annealing of ITO film after wet etching

The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure.

Texturing and Tetragonal Phase Stabilization of ALD HfxZr1-xO2 Using a Cyclical Deposition and Annealing Scheme

In order to enhance the dielectric properties of HfO2, the alloying of HfO2 with ZrO2 was studied. HfxZr1-xO2 films with different Hf:Zr ratios were deposited by atomic layer deposition (ALD) combined with a cyclical deposition and annealing scheme (termed DADA) in which an annealing was performed after every 20 ALD cycles. The impact of the ZrO2 addition on the structural properties of the ALD grown films was investigated by grazing incidence in-plane X-ray diffraction and pole figure measurement using synchrotron radiation as well as transmission electron microscopy and X-ray photoelectron spectroscopy. The HfxZr1-xO2 films with x=1 show the presence of monoclinic (-111) fiber texture. As the Zr content increases, stabilization of the tetragonal phase is observed. The pole figure measurements indicate the presence of tetragonal (111) fiber texture for the ALD HfxZr1-xO2 films with higher Zr content grown by DADA in contrast to random orientation in post deposition annealed films.

Crystallinity of Electrically Scaled Atomic Layer Deposited HfO2 from a Cyclical Deposition and Annealing Scheme

In this work, we present structural characterization of HfO2 films deposited using a cyclical deposition and annealing scheme (termed DADA). Electrical performance improvements were obtained for atomic layer deposited (ALD) HfO2 films grown by use of this DADA process compared to a single deposition followed by a post-deposition anneal (PDA). In order to probe the structural characteristics of films deposited using this DADA process, in this study we utilized grazing incidence in-plane X-ray diffraction and pole figure measurements using synchrotron radiation as well as transmission electron microscopy. Structural differences were investigated from different annealing conditions as well as from different thickness of films. We observed significant differences in structural properties of DADA films compared to films receiving PDA. We also report on the evolution of monoclinic HfO2 with a (1̅11) preferred orientation (fiber texture) for DADA films whereas PDA treatment resulted in a random grain alignment and mixed phase structure.

Correlation between strain and the metal–insulator transition in epitaxial V2O3 thin films grown by Molecular Beam Epitaxy

We report on the deposition of high quality epitaxial V2O3 thin films on (0001) oriented Al2O3 substrates with Molecular Beam Epitaxy. Growth of smooth V2O3 films with root mean square roughness values down to 1Å exhibiting both bulk-like and non bulk-like electrical properties has already been reported in a previous contribution. In this work, the lattice parameters and strain state of deposited films are extracted from both out-of-plane and grazing incidence in-plane X-ray diffraction measurements. Resistivity measurements are performed as a function of temperature using the four-point probe method. We observe a correlation between the in-plane tensile strain and the electrical properties, in particular the room-temperature resistivity. We also compare the electrical data of our V2O3 thin films with the features of the V2O3 bulk phase diagram.

Structural Characteristics of Electrically Scaled ALD HfO2 from Cyclical Deposition and Annealing Scheme

We have recently reported electrical performance improvements in atomic layer deposited (ALD) HfO2 films grown by use of a cyclical deposition and annealing scheme (termed DADA) compared to a single deposition followed by a post-deposition anneal (PDA). We previously proposed a model for bottom-up crystallization in DADA films in contrast to random crystallization for PDA films. To elucidate the mechanisms for this structural modification, in this study we utilized grazing incidence in-plane X-ray diffraction and pole figure measurements using synchrotron radiation as well as transmission electron microscopy. Structural differences were investigated from different annealing conditions as well as from different thickness of films. We observed significant differences in structural properties of DADA films compared to films receiving PDA. We also report on the evolution of monoclinic HfO2 with a (-111) preferred orientation (fiber texture) for DADA films whereas PDA treatment resulted in a random grain alignment and mixed phase structure.

Giant Flexoelectric Effect in Ferroelectric Epitaxial Thin Films

We report on nanoscale strain gradients in ferroelectric HoMnO(3) epitaxial thin films, resulting in a giant flexoelectric effect. Using grazing-incidence in-plane x-ray diffraction, we measured strain gradients in the films, which were 6 or 7 orders of magnitude larger than typical values reported for bulk oxides. The combination of transmission electron microscopy, electrical measurements, and electrostatic calculations showed that flexoelectricity provides a means of tuning the physical properties of ferroelectric epitaxial thin films, such as domain configurations and hysteresis curves.

Impact of various irradiation photon energies and gamma doses on the optical properties of ZnSe nanostructure thin film

ZnSe thin films were prepared by thermal evaporation technique under high vacuum (10−6 Torr) at 300 K and different film thickness. The structure of thin films was measured using grazing incident in-plane X-ray diffraction (GIIXD) and shows single phase zinc blende structure. The particle sizes of the deposited films were estimated for low film thickness by TEM and high film thickness by GIIXD. The particle size of ZnSe films was decreased from ~8.53 to 3.93 nm as film thickness lowered from 200 to 20 nm which ensures the nanocrystalline structure. The optical transmission (T) and reflection (R) in the wavelength range 190–2,500 nm for irradiated and unirradiated ZnSe thin films under investigation were measured. The effect of irradiation of different energies in range (0.1–1.25 MeV) from X-ray, 137Cs and 60Co irradiation sources were studied for ZnSe thin films of 100 and 200 nm thicknesses. The dependence of the absorption spectra and refractive index were investigated for different energies irradiation sources. The ZnSe films show direct allowed interband transition. The effect of particle size of nanocrystalline ZnSe thin films for unirradiated and irradiated by gamma (γ) doses from 137Cs on the optical properties was studied. Both the optical energy bandwidth and absorption coefficient (α) were found to be (γ) dose dependent.