Analysis of Structural and Electrical Properties of Aluminium Doped Lead Sulphide (PbS) Thin Film Prepared by CBD Method

We have deposited PbS and Al doped PbS thin films by chemical bath deposition. Lead acetate and thiourea were used as sources of Pb2+ and S2- respectively. The films were deposited at a pH of 12.5. The deposited films were further annealed at three different temperatures 250 �C, 300 �C, 350 �C. The structural analysis reveals that PbS has a preferential growth at (200) planes and high crystalline PbS were obtained when the films were annealed at 300�C. Crystallite size for all the films varies from 30 to 50 nm. SEM analysis shows almost dense spherical and uniform grains were distributed upon the surface of the film. The Aluminium concentration were varied from (1,2,3 and 4 at %). The electrical conductivity of the Al doped PbS films increases upto to 3 at % and then it decreases at 4 at %. All films exhibits highly stable p-type behavior with maximum conductivity for 3% Al doped PbS films which is 13.32 (Ωcm)-1. Thereby it is concluded that 3% Al is the optimum concentration for the doping for PbS films and can be used for the application of IR detectors and sensors.