Comparison of CdS films deposited from chemical baths containing different doping impurities

The results obtained for CdS films chemically deposited from solutions containing different impurities known as donor type dopants for CdS (chlorine, iodine, boron and indium) are reported. CdS films were deposited onto glass and CuInSe2 absorber substrates at 85 °C. The deposition baths were ammonia solutions containing 0.001 M Cd2+, 0.02 M ammonium compound and 0.002 M thiourea and CdS was deposited at pH 10.3. After deposition, the layers were heated at 200 °C for 30 min in vacuum. The results confirm that the electrical resistivity of CdS films doped with boron and chlorine was dependent on doping level. At the same time, characteristics of CuInSe2 solar cells with differently doped CdS did not show any remarkable dependence on doping level and nature. The buried homojunction model is proposed to explain obtained results.