Some anomalies in the electron transport of Se-doped AlAs

Se-doped AlAs epitaxial layers are grown by metalorganic chemical vapor deposition. The carrier density increases with increasing [H₂Se]/[TMA] and saturates at the ratio of 8xl0^-3. The samples with carrier densities higher than 10¹⁸cm^-3 exhibit almost constant compensating acceptor density values regardless of carrier density and the free-carrier screening effect is conspicuous in this case. Neutral impurity scattering is dominant for the samples with carrier density in the range of 10¹⁸ ~ 10^-19cm^-3 at lower temperatures. A two-band model involving the X- and L-band is adopted for the transport calculation.