Optoelectronical properties of indium sulfide thin films prepared by spray pyrolysis for photovoltaic applications

摘要

Indium sulfide (In_2S_3) thin films have been prepared by the spray pyrolysis (SP) technique using indium acetate and N-N dimethyl thiourea as precursor compounds. Samples prepared at different temperatures and atomic ratio of In to S in the starting solution, (In/S)_(sol), have been characterized using several techniques. X-ray diffraction studies have shown that the preparation temperature (T_p) affects the crystallinity of the deposited materials as well as the optoelectronic properties. For (In/S)_(sol)=1/8, the optical band gap (E_g) increases from 2.2 up to 2.67 eV when T_p increases from 250 up to 450℃. For (In/S)_(sol)=1 and T_p=450℃, the deposited material shows n-type electrical conductivity with a dark value of 1 (Ωcm)~(-1), and E_g=2.04 eV. The In_2S_3 thin films prepared under these conditions have a big potential use as a window material for photovoltaic heterojunction devices.