共查询到20条相似文献,搜索用时 15 毫秒
1.
I. V. Bodnar’ V. F. Gremenok K. Bente Th. Doering W. Schmitz 《Inorganic Materials》2000,36(10):1000-1003
AgInTe2 thin films were deposited onto glass substrates by pulsed laser ablation. Their structure, composition, and transmission
and reflection spectra in the range 0.5 to 2.5 Μm were studied. The absorption coefficient, energies of band-to-band transitions,
and parameters of crystal-field and spin-orbit splittings were determined. The results obtained for the AgInTe2 films are in good agreement with the data for bulk crystals. 相似文献
2.
H. Neumann W. Hörig V. Savelev J. Lagzdonis B. Schumann G. Kühn 《Thin solid films》1981,79(2):167-171
The optical absorption in flash-evaporated CuInS2 thin films was studied in the photon energy range from 0.5 to about 4.2 eV. CuInS2 was found to be a direct gap semiconductor with a gap energy of 1.524±0.005 eV at room temperature. The ground state energy of the free exciton was found to be about 8 meV. An indirect allowed transition was observed at 1.565±0.005 eV and was ascribed to an optical transition from the valence band maxima at the boundary of the Brillouin zone to the lowest conduction band minimum at the zone centre. Three further optical transitions which were probably due to the copper d states in the valence band were found at energies well above the fundamental edge. 相似文献
3.
In the study presented in this paper we attempted to interpret the reflectance and the transmittance of sprayed CdS films. Assuming a model based on multilayer film theory we showed that sprayed CdS film is a combination of multilayer stacks of crystallites and gaseous inclusions. 相似文献
4.
R.C. Linton 《Thin solid films》1974,20(1):17-21
The optical properties of evaporated thin films of zirconium diboride were investigated from 4.1 to 11.3 eV. The optical constants were determined by reflectance measurements made at near-normal and oblique angles of incidence. The existence and energy of interband transitions and the plasma frequency are inferred from these results. 相似文献
5.
6.
7.
8.
9.
《Thin solid films》1986,135(1):35-41
The structure and optical properties of vacuum-deposited films of CuGaSe2 were studied at various substrate temperatures. Stoichiometric films could be obtained at substrate temperatures as low as 450 K. Epitaxial growth was observed on single-crystal NaCl substrates at temperatures above 500 K. The optical transition energies obtained at 1.68, 1.78 and 1.92 eV were in good agreement with previous results. 相似文献
10.
D. K. Suri R. H. Bhawalkar K. C. Nagpal G. K. Chadha 《Journal of Materials Science》1991,26(12):3191-3196
CuGa0.5In0.5Se2 thin films with thickness in the range 50 to 280 nm were deposited by thermal evaporation of prereacted material on glass substrates. The films were found to be polycrystalline with single phase having chalcopyrite structure as that of bulk material. The optical constants of these films were determined by transmittance and reflectance measurements at normal incidence for light in the wavelength range 400 to 1200 nm. Three characteristic energy gaps of 1.30, 1.55 and 2.46 eV were obtained from an analysis of the optical absorption spectrum. The optical constants of the films appear to be independent of the substrate temperature. 相似文献
11.
12.
In this work, VO2 thin films were prepared on three kinds of substrates by the sol-gel dipcoating method followed by heat treatment under vacuum. These thin films were analysed by x-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The infrared and ultraviolet-visible spectra of the VO2 thin films were also recorded during heating and cooling between room temperature and 100°C. The experimental results show that VO2 thin films thus prepared exhibit thermally induced reversible phase transition, and the largest changes in transmittance and reflectivity are approximately 58 and 25%, respectively, in the case of vacuum heat treatment at 400°C and silica glass substrates. The refractive index (n) decreases and the absorption coefficient (k) increases when heating these thin films from room temperature to 100°C, and vice versa for cooling. The reasons why the optical constants and infrared absorption spectra change so remarkably are discussed. 相似文献
13.
《Materials Letters》2005,59(8-9):1085-1088
Thin films of depleted uranium dioxide were made using the sol–gel approach. Films were deposited onto sapphire and MgO substrates that were 0.1 mm thick. Film thickness ranged from 1540 Å to 2470 Å. Intrinsic films were made as were films doped with aluminum, fluorine, phosphorus, nitrogen, and boron. Dopant concentrations ranged from 1019 to 1021 atoms/cc. Optical transmission data obtained on these samples revealed a range in bandgap from 2.0 to 2.5 eV identifying this as a wide bandgap semiconductor. 相似文献
14.
《Thin solid films》1986,137(1):27-37
In2Se3 thin films were grown with good stoichiometry at a substrate temperature around 460 K in the α phase and were shown to remain in the β phase above 480 K. The Hall coefficient and the d.c. conductivity of polycrystalline In2Se3 films grown on Pyrex and mica substrates were studied in the temperature range 77–530 K. After thermal treatment above 473 K of the α phase thin film, the electrical resistivity decreased and the sample remained in an irreversible phase. This is explained in terms of structural changes at high temperatures. The mobility behaviour of the β phase annealed thin films is illustrated. We use the Petritz barrier model to explain the activation energy of the mobility as due to the grain boundaries of the polycrystallites.The optical properties (refractive index and absorption coefficient) are also reported. The direct band gaps of In2Se3 thin films are 1.43 eV and 1.55 eV for the α phase and β phase respectively. These values are obtained from transmission measurements and are confirmed through photoconductivity measurements. 相似文献
15.
The transmission of vacuum deposited Cd3As2 films has been measured in the spectral range 0.6–15 ωm. The absorption coefficient α has been calculated from the data for crystalline films obtained at substrate temperature Ts = 440 K and also for amorphous films obtained on substrates at Ts = 300?393 K. The position of the low-energy absorption edge in the spectral range 0.1–0.3 eV is discussed and the value Δgopt = 0.06 eV for indirect transion Γ → Γ15 is obtained for crystalline films. For amorphous films, a shift of the minimum absorption edge to was observed. For higher energies two direct transitions have been established: the first at E1 = 0.9 eV in the photon energy range 0.9–1.2 eV.and the second at E2 = 1.2?1.3 eV in the photon energy range 1.3?1.6 eV. The last value is in good agreement with the value calculated by Lin Chung and with reflectivity data; it corresponds to the transition Γ15 → X1 in the hypothetical band model of Lin Chung. Differences in the reflective index values for crystalline and amorphous Cd3 As2 are also discussed. 相似文献
16.
H. S. Soliman T. Hindia H. Abo Dorra E. Hashem 《Journal of Materials Science: Materials in Electronics》1994,5(4):248-254
CdGa2Se4 thin films were prepared by vapour deposition onto either room temperature or preheated quartz and glass substrates (T
S) or they were deposited at room temperature and then annealed at about (T
A) 623 K. The films thus prepared were crystalline with a thiogallate tetragonal structure. The optical constants (the refractive index n and the absorption index, k) were determined for CdGa2Se4 films deposited onto quartz substrates held at either room temperature or at T
S = 573 K. These constants were also determined for preannealed films (T
A = 623 K). Plots of (hv)2 = f(hv) and (hv)1/2 = g(hv) were linear, indicating the existence of both direct and indirect optical transitions. It was found that the values of E
g
d and E
g
ind for as-deposited CdGa2Se4 films were 2.46 and 1.91 eV, respectively. The corresponding values for the annealed films and the films deposited at T
S = 573 K were 2.56 and 2.06 eV, respectively. 相似文献
17.
18.
V. J. Rao Madhuri V. Salvi V. Samuel A. P. B. Sinha 《Journal of Materials Science》1985,20(9):3277-3282
Conditions have been developed for the deposition of a stoichiometric thin film of zinc phosphide (Zn3P2) using electron beam evaporation. Structural properties of as-deposited and annealed thin films of zinc phosphide have been
studied using electron and X-ray diffraction. The as-deposited film is non-crystalline, structural ordering starts on annealing
at 200° C and the film becomes crystalline at 300° C with the structure matching that of the bulk material. Optical absorption
has been investigated over the range 1 to 3 eV with emphasis on the region of interband absorption. The thin film absorption
edge is found to be exponential for lower values of absorption coefficient. Analysis of thin film data showed that Zn3P2 is a direct-band-gap material. On annealing there is a shift in the band edge towards higher energy.
NCL Communication No. 3571. 相似文献
19.
MAHDI H SUHAIL 《Bulletin of Materials Science》2012,35(6):947-956
Copper indium sulphide (CIS) films were deposited by spray pyrolysis onto glass substrates from aqueous solutions of copper (II) sulphate, indium chloride and thiourea using compressed air as the carrier gas. The copper/indium molar ratio (Cu/In) in the solution 1(1:1) and the sulphur/copper ratio (S/Cu) was fixed at 4. Structural properties of these films were characterized. The effects of Zn (0–5%) molecular weight compared with CuInS2 Source and different substrate temperatures on films properties were investigated using X-ray diffraction (XRD) and optical transmission spectra. Optical characteristics of the CuInS2 films have been analysed using spectrophotometer in the wavelength range 300–1100 nm. The absorption spectra of the films showed that this compound is a direct bandgap material and gap values varied between 1·55 and 1·57 eV, depending on the substrate temperatures. Zn-doped samples have a bandgap energy of 1·55–1·95 eV. It was observed that there is an increase in optical bandgap with increasing Zn % molecular weight. The optical constants of the deposited films were obtained from the analysis of the experimentally recorded transmission and absorption spectral data. The refractive index, n and dielectric constants, ε 1 and ε 2, were also discussed and calculated as a function of investigated wavelength range and found it dependent on Zn incorporation. We found that the Zn-doped CuInS2 thin films exhibit P-type conductivity and we predict that Zn species can be considered as suitable candidates for use as doped acceptors to fabricate CuInS2-based solar cells. The paper presents a study concerning the influence of deposition parameters (temperature of the substrate and concentration of Zn (1–5)% from 0·16 M ZnCl2) on the quality of CuInS2 thin films achieved by spray pyrolysis on glass substrate from solutions containing 0·02 M CuCl2·2H2O, 0·16 M thiourea and 0·08 M In2Cl3·5H2O. 相似文献
20.
Y. Sripathi G. B. Reddy L. K. Malhotra 《Journal of Materials Science: Materials in Electronics》1991,2(2):109-111
Smooth and pinhole-free thin films of Ga5Ge19Te76 have been obtained by vacuum evaporation. The as-deposited films are amorphous. Thermal annealing at 222°C leads to an amorphous-to-crystalline transition. A maximum contrast of 30% in reflectivity (measured at 1 µm) has been obtained on phase transition from amorphous to crystalline state. The optical constants and the bandgap are reported. 相似文献