Changes of PbSnTe thin film thickness due to the oxidation by different methods

Nanostructures based on PbTe seem promising for production of thermoelectric converters. However surface oxidation of nanoparticles that occurs during the manufacturing processes can significantly change the nanocrystals' dimensions and properties. Three oxidation methods, i.e. thermal, electrochemical and chemical, were compared with the objective to minimize the loss of semiconductor material during the oxidation. Correlation between thickness of an oxide layer and a semiconductor material layer used to grow the oxide were determined from Auger Electron Spectroscopy profiling through PbTe and Pb0.8Sn0.2Te epitaxial layers down to the BaF2 substrate. The thermal oxidation was found to ensure minimum semiconductor material loss. In addition, material loss in electrochemical processes can be reduced through appropriate choice of solvents.