Optical and electrical characterization of high-resistivity liquid-phase-epitaxial In0.53Ga0.47As:Fe

Abstract

Semi-insulating In0.53Ga0.47As with carrier concentration n=1.2×1012 cm−3, resistivity up to 1090 Ω cm, and mobility up to 9500 cm2/V s at 300 K is grown by liquid-phase epitaxy and doping with Fe. The influence of Fe doping on the photoluminescence of In0.53Ga0.47As is systematically investigated. An acceptor level at Ev+150 meV, tentatively assigned to Fe by some of us earlier, is definitively identified as an Fe-related complex. This acceptor level, however, is not responsible for the semi-insulating behavior of In0.53Ga0.47As as shown by statistical calculations. High-resolution deep-level transient spectroscopy experiments show two deep acceptors at EC−ET=0.44 and 0.30 eV, respectively. The first one, which dominates, is identified as being caused by the Fe3+/Fe2+ acceptor level. The second, somewhat weaker one, might be caused by the O-related trap recently discovered by Loualiche et al. [Appl. Phys. Lett. 51, 1361 (1987).] Combining the Fe acceptor energy position in In0.53Ga0.47As with its known value in InP and the known conduction-band discontinuity of the InP/In0.53Ga0.47As heterointerface we find that the vacuum referred binding energy model is approximately but not strictly valid. In this model the transition-metal impurity levels are aligned with respect to the vacuum level across interfaces regardless of the surrounding host crystal environment.