Optical and photovoltaic properties of indium selenide thin films prepared by van der Waals epitaxy

Indium selenide thin films have been grown on p-type gallium selenide single crystal substrates by van der Waals epitaxy. The use of two crucibles in the growth process has resulted in indium selenide films with physical properties closer to these of bulk indium selenide than those prepared by other techniques. The optical properties of the films have been studied by electroabsorption measurements. The band gap and its temperature dependence are very close to those of indium selenide single crystals. The width of the fundamental transition, even if larger than that of the pure single crystal material, decreases monotonously with temperature. Exciton peaks are not observed even at low temperature, which reveals that these layers still contain a large defect concentration. The current–voltage characteristic of indium selenide thin film devices was measured under simulated AM2 conditions. The solar conversion efficiency of these devices is lower than 0.6%. The high concentration of defects reduces the diffusion length of minority carriers down to values round to 0.2 μ[email protected] ; [email protected]

Thin film bismuth(III) sulfide/zinc sulfide composites deposited by spray pyrolysis

(Bi2S3)(x)(ZnS)(1-x) composites in thin films were successfully grown on glass substrates by the spray pyrolysis technique. The films growth were prepared by the reaction of aqueous solutions of bismuth(III) chloride (BiCl3) and zinc chloride (ZnCl) with Thiourea on substrates heated to a temperature of 280 °C. The structural properties have been identified using X-ray diffraction spectra. The deposited films are of polycrystalline natures. The both of the two phases mixed (Bi2S3 and ZnS) were well observed in the X-ray diffraction plots. The optical properties were also studied using transmittance and reflectance measurements in the wavelength range (200–2500 nm). Optical gaps were evaluated; we are found that (Bi2S3)(x)(ZnS)(1-x) (x = 0–1) composites in thin films are characterized by two optical gaps limited between the gap of Bi2S3 and that of ZnS films in the pure phase. Keywords: Thin films, (Bi2S3)(x)(ZnS)(1-x), Composite materials, Structural and optical propertie

(MoO 3 ) 1−x (V 2 O 5 ) x thin films: Elaboration and characterization

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Structural and optical properties of MoO3 and V2O5 thin films prepared by Spray Pyrolysis

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Site location of Al-dopant in ZnO lattice by exploiting the structural and optical characterisation of ZnO:Al thin films

The zinc oxide thin films, highly transparent, doped aluminium were prepared on glass substrates by the reactive chemical spray method. The incorporation nature of Al atoms in the ZnO lattice was determined by X-ray diffraction and optical analyses. Indeed, for low doping ⩽2%, the results of X-ray spectra analysis show a simultaneous reduction of lattice parameters (a and c), this variation, which follows VEGARD’s law, tends to indicate a substitution of Zn by Al. By against for doping >2% the increase in the lattice parameters thus the grain sizes, in accordance with the VEGARD’s law can be explained by occupation of the interstitial sites by Al atoms. Beyond 4%, the material tends to get disorderly and the crystallites orientation is random. The studied optical properties show that the variation of the optical gap follows a law of the x3/2 form for x < 3% (x is the aluminium atom fraction incorporated in the ZnO lattice). The granular structure is fairly visible and some local growths are disrupted. The crystallite size at low enlargement is coherent with the XRD results. Keywords: Al-doped ZnO thin films, XRD, Substitutional and interstitial sites, Band gap, SE

Effect of substrate temperature on the structural and optical properties of MoO3 thin films prepared by spray pyrolysis technique

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Raman and optical studies of spray pyrolysed Sb&#60;inf&#62;2&#60;/inf&#62;S&#60;inf&#62;3&#60;/inf&#62; thin films

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