I want to deposit thin of AgBiS on glass substrate.For this I am using silver nitrate, bismuth nitrate pentahydrate and thiourea as source of Ag, Bi & S respectively in proportion 0.08M, 0.02M and 0.1M. All solutions are prepared in distilled water with constant stirring. Later Ag solution is added with TEA (colour becomes dark brown) and then drop by drop ammonia till solution becomes colourless. When I the solution of Bi & S to the Ag solution the becomes black and when stirring is stopped the precipitate settles down.Hence I am not able to deposite AgBiS thin onto glass substrate.Can any one tell me why this is happening so?And how can I deposite AgBiS thin film by CBD technique?