SnS thin films were prepared using automated chemical spray pyrolysis (CSP) technique. Single-phase, p-type, stoichiometric, SnS films with direct band gap of 1.33 eV and having very high absorption coefficient (N 10 5 /cm) were deposited at substrate temperature of 375°C. The role of substrate temperature in determining the optoelectronic and structural properties of SnS films was established and concentration ratios of anionic and cationic precursor solutions were optimized. n-type SnS samples were also prepared using CSP technique at the same substrate temperature of 375°C, which facilitates sequential deposition of SnS homojunction. A comprehensive analysis of both types of films was done using x-ray diffraction, energy dispersive x-ray analysis, scanning electron microscopy, atomic force microscopy, optical absorption and electrical measurements. Deposition temperatures required for growth of other binary sulfide phases of tin such as SnS 2 , Sn 2 S 3 were also determined.

Thin films of undoped and In-doped zinc oxide, prepared using chemical spray pyrolysis, were investigated using x-ray diffraction, optical transmission and absorption spectra, SEM, resistivity measurements, x-ray photoelectron spectroscopy and photoluminescence studies. A doping level of 1 at% indium was found to give lowest resistive films and enhanced optical transmission. But increasing the doping percentage resulted in lower optical transmission. XPS investigations revealed the presence of elemental chlorine in the In-doped film. Undoped ZnO thin films gave a strong blue-green emission. Doping with indium apparently resulted in a competitive phenomenon that overshadows the blue-green emission and gave rise to three emissions at 408, 590 and 688 nm.

No abstract

Indium sulfide thin films have been prepared using the chemical spray pyrolysis technique. Samples with different substrate temperatures and indium-to-sulfur (In/S) ratios have been prepared and characterized using x-ray diffraction (XRD), x-ray photoelectron spectroscopy, photosensitivity measurements and optical absorption studies. XRD studies have revealed that the samples are β-In 2 S 3 . The optical bandgap has been found to decrease from 2.81 to 2.64 eV with the In/S ratio varying from 2/1 to 2/8. The photoresponse of the samples can be improved by changing either the In/S ratio in the solution or the substrate temperature. From this study we observe that, in terms of crystallinity, bandgap and photoresponse, the sample with the In/S ratio of 1.2/8 is very suitable for any photovoltaic application.

No abstract