C. Ravi Dhas

Effect of sputtering power on properties and photovoltaic performance of CIGS thin film solar cells

CuInGaS2 (CIGS) thin films were fabricated by DC magnetron sputtering by varying the sputtering power (70, 90, 110 and 130 W). The X-ray diffraction revealed the formation of tetragonal structure with (1 1 2) preferential orientation. The film prepared at 90 W has better crystallinity with minimum dislocation density and strain. From the scanning electron microscopy analysis, it was found to be a denser and larger in grain formation. The elemental quantification and stoichiometric ratio of the CIGS films were confirmed by energy-dispersive spectra. The optical band gap was found using Tauc plot, and it varied from 1.20 to 1.52 eV. The transport conduction mechanism involved in CIGS films was identified from DC four-probe method. Raman studies reveal that all the films composed of CH and CA ordering. The solar cell measurements indicate that high power conversion efficiency (η) of 0.29% and short-circuit current density of (Jsc) of 4.51 mA/cm2 obtained for the film deposited at 90 W.

CuInS 2 Layer Deposition Through Nebulizer Spray Technique for Solar Cell Fabrication

CuInS2 (CIS ) thin films were fabricated by jet nebulizer spray technique at various substrate temperatures such as 250, 300, 350 and 400 °C. The XRD revealed the formation of chalcopyrite crystalline phase with (1 1 2) preferential orientation. The film prepared at 300 °C has better crystallinity with minimum dislocation density and strain. The microstructure of the prepared CIS thin films was investigated by means of scanning electron microscope (SEM ). The elemental quantification and stoichiometric ratio of the CIS films were confirmed by EDS. The conductivity of CIS thin films was carried out by four probe method and it showed that all the films were in semiconducting nature. The optical band gap was found using Tauc plot and it was varied from 1.3 to 1.45 eV. A peak around 298 cm−1 was observed in Raman spectra attributed to the mixture of both CH- and CA-ordering.

Structural, Optical and Ethanol Gas Sensing Performance of Aluminium Doped Zinc Oxide (AZO) Thin Films by Nebulizer Spray Technique

Aluminium doped zinc oxide (AZO) nano—structured films were deposited by nebulizer spray technique. The role of aluminium dopant concentration over the structural, optical and electrical properties was examined by different analytical techniques. The structural results from X-ray diffraction showed that preferential orientation of films obtained along the (002) direction. The surface morphology of the films showed a hexagonal facet with the nano—structured film. The parameters such as resistivity and activation energy were determined from electrical studies. The sensitivity of the films towards ethanol gas was investigated at room temperature.