Effect of heat treatment on properties of CuInS2 thin films grown by ion layer gas reaction

CuInS2 thin films were prepared on glass substrates by ion layer gas reaction method using a CH3CN solution of CUCl2 and InCl3. The effect of heat treatment on the structural, chemical, morphologic development and optical and electrical properties of CuInS2 thin films was investigated. The results showed there is residual CuxS impurities on CuInS2 thin films until heat treatment temperature is over 450 degrees C, and CuInS2 thin films annealed at 550 degrees C for blow 0.5 h is amorphous, and film annealed at 550 degrees C for 1 h is chalcopyrite structure with (112) perfected orientation. It was found that Cu/In increases and S/(Cu+In) decreases with increasing the heat treatment temperature. The surface of CuInS2 thin films become more smooth and uniform with increasing the temperature, but are coarser if the heat treatment time was overran 1.0 h. The absorption coefficient of CuInS2 thin films is larger than 10(4) cm(-1), and the band gap E-g, carrier concentration and mobility increase from 1.29 eV to 1.37 eV, 10(15) cm(-3) to 10(17) cm(-3) and 3.9 cm(2)/V(.)s to 33.9 cm(2)/V(.)s, respectively, and resistivity decrease form 2850 Omega(.)cm to20.5 Omega(.)cm with increasing heat treatment temperature form 250 degrees C to 550 degrees C.