Thermal and Electrical Transport in InAs-GaAs Alloys

The thermal conductivity, Seebeck coefficient, and electrical resistivity have been measured as a function of temperature for various impurity concentrations and alloy compositions. Room-temperature measurements of Hall mobility and the optical determination of electron effective masses have been made. n-type alloys between 50 and 70 mole % InAs, doped with selenium to give room-temperature resistivities of 4 to 8×10−4Ω·cm, give an optimum figure of merit. The maximum figure of merit at 700°K was measured to be 0.98×10−3 deg−1· p-type alloys (30%–70% InAs) doped with zinc gave a maximum figure of merit of only 0.4×10−3 deg−1 at 700°K. The room-temperature Hall mobilities and Seebeck coefficients of the p-type alloys are lower than might be anticipated. The electron effective masses were found to vary uniformly with composition.