AlGaSb/GaSb quantum wells grown on an optimized AlSb nucleation layer

Abstract

Five-period AlGaSb/GaSb multiple quantum wells (MQW) are grown on a GaSb buffer. Through optimizing the AlSb nucleation layer, the low threading dislocation density of the MQW is found to be (2.50 ±0.91) × 108 cm-2 in 1-μm GaSb buffer, as determined by plan-view transmission election microscopy (TEM) images. High resolution TEM clearly shows the presence of 90° misfit dislocations with an average spacing of 5.4 nm at the AlSb/GaAs interface, which effectively relieve most of the strain energy. In the temperature range from T = 26 K to 300 K, photoluminescence of the MQW is dominated by the ground state electron to ground state heavy hole (e1-hh1) transition, while a high energy shoulder clearly seen at T > 76 K can be attributed to the ground state electron to ground state light hole (e1-lh1) transition. © 2010 Chinese Institute of Electronics.