In2S3 was deposited by chemical bath deposition on the Sb2S3 thin films using a solution of 0.971 g of In2(SO4)3 (25 mM), 0.563 g of CH3CSNH2 (0.1 M) and 0.43 ml CH3COOH (0.1 M) in 75 ml de-ionized water. All the chemicals were first dissolved in 75 ml de-ionized water in a beaker and then placed in a bath pre-heated to 70°C. After about 45 mins, a faint yellow precipitate was formed, which is the indication that In2S3 has started to precipitate, and then the Sb2S3 thin films were immersed for a duration of 15 mins. Next, the films were thoroughly rinsed with de-ionized water and dried under a stream of nitrogen.