Shubnikov-de Haas effect and persistent photoconductivity in In0.52Al0.48As

The Shubnikov-de Haas effect in InAlAs measured using pulsed magnetic field s up to 50 T is reported. The InAlAs samples were grown by molecular beam e pitaxy (MBE) and were either delta or slab doped with silicon at densities up to 7 x 10(12) cm(-2). Comparison of experimental subband densities with those calculated self-consistently shows that spreading of Si occurs by sur face segregation at growth temperatures of similar to 520 degrees C, simila r to its behavior in MBE-grown InGaAs. In contrast to InGaAs, the InAlAs ex hibits persistent photoconductivity which appears to be caused by a bulk de fect rather than DX(Si) states. (C) 1999 American Institute of Physics. [S0 021-8979(99)00423-5].