Far-infrared photoconductivity spectroscopy of high-mobility n-GaAs grown by MBE

Abstract
N-GaAs of high peak mobility ( mu =250000 cm2 V-1 s-1) has been grown in a molecular beam epitaxy (MBE) system with modified source-furnace geometry. High-resolution far-infrared magnetospectroscopy has been performed on this material. The photoconductive response at 2-4 K reveals a rich spectrum of excited state transitions. These are identified from theoretical models, and transitions from the ground impurity state up to the N=8 Landau level are noted. For the first time in MBE material, transitions involving D- states are observed.