Cubic PbS thin films on TCO glass substrate by galvanic technique

摘要

We report an electrochemical deposition of PbS thin films on SnO_2:F coated Transparent Conducting Oxide (TCO) glass substrates from a solution of EDTA, Pb(OAc)_2 and Na_2S_2O_3. A Pb strip acted as a sacrificial anode, while the TCO glass was the cathode. No external bias was applied. The deposition of PbS thin films was pH sensitive and a pH around 3 was found to be optimum for film deposition. The deposition was carried out at 80 deg C, with stirring of the solution. X-ray diffraction studies revealed that the PbS films were of cubic phase. Scanning electron microscope image analysis showed a highly compact surface morphology. IR spectrum yielded an energy band gap around 0.4 eV. A.C. current-voltage (I-V) measurements were carried out using gold as one of the contacts. It was found that the PbS film formed an ohmic contact when the other electrode was also gold, however, a Schottky junction resulted, when the second contact was TCO.