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Synthesis of CdS thin films were carried out onto glass substrates by chemical bath deposition (CBD) method using CdCl2asCd 2+ and thiourea as S 2-ion source with ammonia as a complexing agent. Influence of bath temperature on structural, morphology and optical properties has been systematically and carefully investigated. XRD analysis revealed that the synthesized CdS films are nanocrystalline having hexagonal structure with (002) preferential orientation. Estimated crystallite size was found in the range 16-32 nm. The UV-Visible spectroscopy analysis showed that the films have high transmission (> 70 %) in visible and NIR region of solar spectrum. Optical band gap was found > 2.3 eV over the entire range of bath temperature studied. The Raman spectra for the CdS films deposited at various bath temperatures shows a continuous shift of 1 LO phonon peak towards higher frequency which suggest the improvement of structural order with increase in bath temperature. The increase in the intensity ratio, 2LO/1LO with bath temperature indicates enhancement of crystallinity of CdS films with increase in bath temperature. The SEM analysis showed that CdS films deposited at various bath temperatures are smooth, homogeneous, and nearly uniform with randomly oriented spherical nanocrystallites.

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Structural, optical, and electrical properties of hydrogenated silicon carbide (SiC:H) films, deposited from silane (SiH4) and methane (CH4) gas mixture by HW-CVD method, were investigated. Film properties are carefully and systematically studied as function of deposition pressure which is varied between 200 mTorr and 500 mTorr. The deposition rate is found to be reasonably high (9.4 nm/s<rd<15.54 nm/s). Formation of SiC:H films is confirmed by FTIR, Raman, and XPS analysis. XRD and Raman analysis revealed that with increasing deposition pressure amorphization occurs in SiC:H films. FTIR spectroscopy analysis shows that bond density of C–H decreases while Si–C and Si–H bond densities increase with increasing deposition pressure. Total hydrogen content increases with increasing deposition pressure and was found to be <20 at.%. The absence of band ~1300–1600 cm−1in the Raman spectra implies negligible C–C bond concentration and formation of nearly stoichiometric SiC:H films. The band gap shows increasing trend with increasing deposition pressure. The high value of Urbach energy suggests increased structural disorder in SiC:H films. Finally, it has been concluded that CH4can be used as effective carbon source in HW-CVD method to prepare stoichiometric SiC:H films.

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