Self-organization of quantum wire-like morphology on In xGa 1 − xAs single quantum wells grown on (100)InP vicinal surfaces depending on the substrate misorientation, buffer mismatch and growth temperature

Abstract

The appearance of a quantum wire-like morphology on the In x Ga 1 − x As single quantum well of High Electron Mobility Transistor structures grown by Molecular Beam Epitaxy (MBE) on (100)InP vicinal surfaces is reported. This quantum wire morphology in the InGaAs well is driven by the lateral modulation existing in the In y Al 1 − y As tensile buffer of the heterostructure. The development of the lateral modulation in the buffer, related to In-rich or Alrich regions oriented along {133} or {122} planes, has been found to be favoured by the presence of steps at the interface of 4° off (100) towards (111)A misoriented InP substrates and also attributed to a thermally activated phenomenon. Furthermore, the results of Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) reveal that the lateral composition modulation acts as a strain relieving mechanism that accommodates the tensile mismatch between the InAlAs buffer and the substrate.