Influence of Mn doping on structural, optical and photoluminescence properties of Cd_(0.98)Co_(0.02)S thin films by chemical bath deposition method

摘要

Cd_(0.98)Co_(0.02)S and Mn-doped Cd_(0.98)Co_(0.02)S thin films have been successfully deposited on glass slides using aqueous ammonia solution at pH = 9.5 by chemical bath deposition method. X-ray diffraction pattern showed the cubic phase of the deposited films which was not affected by Mn-doping. Reduced crystallite size and decrease of interplanar distance confirmed the proper substation of Mn~(2+) into Cd-Co-S. Microstructure revealed that the spherical like structure of Cd_(0.98)Co_(0.02)S is changed into more compact plate like structure by Mn-doping. The enhanced visible light absorption by Mn doping proved that Mn-doping is an effective way to utilize the solar energy and enhance its photocatalytic activity under visible light. Infra red showed the shift of wave number from 597 cm~(-1) (Cd_(0.98)Co_(0.02)S) to 641 cm~(-1) (Co_(0.97)Co_(0.02)-Mn_(0.01)S) corresponding to Cd-S bond which confirmed the lower crystallite size. The observed blue emission band attributed to inter-band radiation combination of photo-generated electrons and holes and the change in its intensity and peak position were explained by recombination centers and impurity induced defect states.