Current-Voltage Characteristic and Schottky Barrier Height of the GaAlAsSb(p)/GaSb(n+) Heterostructure

Abstract

The GaAlAsSb/GaSb is an interesting system for optoelectronic device technology and particularly for the preparation of lasers and photodetectors. The current-voltage characteristic of Ga 0.53 Al 0.47 As 0.04 Sb 0.96 (p)/GaSb(n þ ) heterojunctions, obtained by liquid phase epitaxy on GaSb substrate, is studied. The current of the heterojunction, which is essentially a thermoionic emission of holes, has a behavior identical to that of the Schottky diode, allowing to derive the barrier height V b ¼ 685 meV for this heterostructure. The Richardson constant of the system is calculated to be 49.1 A cm À2 K À2 . The band offsets at the interface are determined as DE c ¼ 460 meV, DE v ¼ 128 meV, in agreement with other works. The variation of the valence band offset with Al composition shows a good agreement with the theoretical models proposed by Jaros and Mujica.