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 8x10(-3). The samples with carrier densities higher than 10(18)cm(-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 10(18)similar to 10(19)cm(-3) at lower temperatures. A two-band model involving the X- and L-band is adopted for the transport calculation.