Electrical transpoet properties of SiGe thermoelectric alloys doped with As, P, and As+P

Abstract

The Hall coefficient RH, Seebeck coefficient, and electrical resistivity have been measured on hot-pressed SiGe alloys (80 at.% Si) from 4 to 300 K. The alloys were doped with As, P, or As+P from 5×1018 to 1.75×1020 cm−3. Only slight differences in transport properties with dopant type were observed. Studies of dopant solubilities were pursued, and the results suggest that the limiting electrical active As concentrations are below those of P. In the analysis of the transport data the standard treatment of ionized impurity scattering was found to be inadequate. The theory, when modified to include the energfy dependence of the screening factor, gives an adequate description of our data. Hall factors were determined from RH data and dopant concentrations obtained from chemical analysis. Hall factor were also determined from analysis of the transport data and were about 20% smaller than those based on dopant concentrations deduced from chemical analysis.