Influence of antimony (Sb) concentration and temperature on the properties of Sprayed Sb-doped CuInS2 thin films for solar cell applications

摘要

Copper Indium Disulphide (CuInS2) is an absorber material for solar cells and Photovoltaic applications. By suitably doping the material with the suitable dopants such as Bi, Zn, Na, P, Cd, Sn, N, and As its structural, optical, Photoluminescence properties and electrical conductivities could be controlled and modified. It is observed that the film growth temperature, the ion ratio (Cu / In =1.25) and Sb- doping affects the structural, optical and photoluminescence properties of CuInS2 thin films grown in the temperature range of 300–4000 C.The XRD patterns confirm that the Sb-doping suppresses the growth of polycrystalline CuInS2 ( 0.02M Sb-doping ) along (112) preferred plane. From the crystallographic parameter measurements, it is found that the 0.01M Sb-doped CuInS2 thin films show better crystalline quality than 0.02M doped samples. Improved optical transmittance properties are observed in 0.02M Sb- doped samples in the wave length range 350-1100nm. The optical absorption coefficient (α (hν)) for the Sb- doped samples (0.02 M) is found to be in the order of 10 5 cm-1. The optical band gap (Eg) energies for 0.02M Sb-doped CuInS2 thin films increase with increase of temperatures from 300–4000C. SEM patterns reveal that, large size crystals of (1μm) flower like structure are formed on the surface for 0.02M doped samples. Well defined sharp blue and green band emissions are observed in PL spectra and defects related PL spectra are discussed.