Structural and optical properties of Pr doped CuInS2 thin films synthesized by chemical bath deposition

Abstract

The Pr doped CuInS2 thin films have been prepared by chemically bath deposition technique at 80°Ctemperature. The semiconducting films are grown in bath containing aqueous solution of copper (II) chloride dihydrate, Indium (III) chloride, thiourea, TEA, ammonia (25%). Pr is used as the doping element. Chloride dehydrates is used for the copper ion source, Indium chloride for indium ion source and thiourea for sulphur ion source, TEA is a complexing agent and ammonia maintains the pH. The SEM Studies of Pr doped CuInS2 films show that at lower volume polyhedral shaped particle appears on the surface. No voids are seen. But at higher volume of Pr; voids are seen on the surface. Particle looks like accumulated woolen balls or cubic like grains. Agglomeration of particle increases with volume and hence particle size also increases. In the XRD of prepared sample characteristic peaks of chalcopyrite phase appears between (240- 800) in all the films. Hall measurement shows that resistivity of Pr (6ml) doped film is very high. The conductivity of all doped films is higher than undoped film. In general, increased doping will leads to increased conductivity. In the Photoluminescence study the emission peak appears at wavelength 575nm, 550nm and 525nm wavelength. High transmittance, low reflectance found in the visible region in the entire prepared sample. The absorption peaks fall in the visible region. High Photocurrent is found, and in dark current study the linear behavior between voltage and current are seen. Quite good photosensitivity is observed in Pr doped CuInS2 films.