Atomic ordering and temperature-dependent transient photoconductivity in Ga0.47In0.53As

Influences of CuPtB atomic ordering on transient photoconductivity in epitaxial Ga0.47In0.53As films grown by metal-organic chemical vapor deposition are examined. Low-injection lifetimes of several ms are measured in double-variant ordered samples at 77 K; these lifetimes decrease rapidly with temperatures above 180 K, giving a thermal activation energy for recombination of 0.19 eV. Single-variant ordered samples exhibit typical lifetimes of 30-60 mu s, with no noticeable temperature dependence up to 300 K. Charge separation in double-variant samples may be driven by a type-II band alignment between ordered and disordered regions, or by an alternating internal electrical polarization between ordered variants. Recombination in both double- and single-variant samples may be influenced by inhibited transport across antiphase boundaries. (C) 1999 American Institute of Physics. [S0003-6951(99)05223-7].