Electron mobility and physical magnetoresistance in n-type GaSb layers grown by molecular beam epitaxy

Electron mobility and low-field transverse physical magnetoresistance were measured in Te-doped GaSb layers grown by molecular beam epitaxy. The samples investigated had electron densities ranging from 10(16) to 10(18) cm(-3); measurements were taken in the 8-300 K temperature range. The high mobility values demonstrate that SnTe can be used as a source of Te doping with results comparable with GaTe. A detailed analysis of the magnetoresistance data demonstrates that in samples with high electron density (n approximate to 10(18) cm(-3)) the magnetoresistance is mainly due to mixed conduction of electrons in both Gamma and L conduction band minima: the analysis gives the temperature dependence of the mu(Gamma) and mu(L) mobilities and of the E(L) - E(Gamma) energy separation between L and Gamma edges. E(L) - E(Gamma) is 82 meV at 300 K and 67 meV at 8 K and exhibits a non-monotonic behaviour within the temperature range explored. In samples with low electron density (n approximate to 10(16) cm(-3)) the magnetoresistance is mainly due to the energy distribution of carriers in the Gamma valley.