Piezoresistance and Piezo-Hall Effects inn- andp-Type Aluminum Antimonide

Abstract

Measurements have been made between 77 and 362°K of the effect of uniaxial compression (up to 2×${10}^8$ dyn/${\mathrm{cm}}^2$) on the resistivity and Hall coefficient of oriented single-crystal samples of $n$- and $p$-type AlSb of nondegenerate carrier concentrations. Measurements were also made at 195 and 298°K employing hydrostatic pressures up to 4.5×${10}^9$ dyn/${\mathrm{cm}}^2$. The piezoresistance results on $n$-type material indicate that the conduction band of AlSb is multivalleyed with valleys along $〈100〉$ axes in k space. The temperature dependence of the piezoresistance coefficient ${\pi }_{11}$ over most of the temperature range is explained by means of the deformation-potential theory for electron transfer with no intervalley (IV) scattering. The shear-deformation-potential constant, ${\Xi }_u$, is found to be given by ${{\Xi }_u}^{\circ }(1+\alpha T)$, where ${{\Xi }_u}^0=4.9\mathrm{}\pm 0.4$ eV and $\alpha =(1.0\mathrm{}\pm 0.4)\times {10}^{-3\mathrm{}}°$ ${\mathrm{K}}^{-1\mathrm{}}$. Between 195 and 112°K, ${\pi }_{11}$ is almost independent of temperature for unknown reasons, but this behavior does not seem to be due to IV scattering. For $p$-type material, only ${\pi }_{44}$ is found to be large and, over much of the temperature range measured, to depend on temperature as predicted by deformation-potential theory. These results, when combined with magnetoresistance results of others, indicate that AlSb has a degenerate valence-band edge similar to germanium and other III-V semiconductors. Results of the piezo-Hall-effect measurements on both $n$- and $p$-type material are in qualitative accord with the type of extrema obtained from the piezoresistance measurements.