Chemical Vapor Deposition and Ion Beam Modification of Thermoelectric Materials

摘要

Silicon-germanium alloys of approximately 20% germanium (a material which is used for thermoelectric generators) have been grown in thin-film form by chemical vapor deposition and doped by ion implantation. The materials appear to have a very small grain size, which reduces the carrier mobility and compensates donors; samples implanted with phosphorus were still found to be p-type. The Seebeck coefficients and resistivities were measured up to 1000 C; measurements agree with theoretical calculations. The results indicate that if the grain size were increased to the optimum value of approximately one micron, thermoelectric figure of merit similar to that of bulk materials could be expected. Possible ways of incorporating thin-film CVD processes into current thermoelectric technology are discussed.