SELF-ORGANIZATION OF QUANTUM WIRE-LIKE MORPHOLOGY ON INXGA1-XAS SINGLE QUANTUM-WELLS GROWN ON (100)INP VICINAL SURFACES DEPENDING ON THE SUBSTRATE MISORIENTATION, BUFFER MISMATCH AND GROWTH TEMPERATURE

The appearance of a quantum wire-like morphology on the InxGa1-xAs sin gle quantum well of High Electron Mobility Transistor structures grown by Molecular Beam Epitaxy (MBE) on (100)InP vicinal surfaces is repor ted. This quantum wire morphology in the InGaAs well is driven by the lateral modulation existing in the InyAl1-yAs tensile buffer of the he terostructure. The development of the lateral modulation in the buffer , related to In-rich or Al-rich regions oriented along {133} or {122} planes, has been found to be favoured by the presence of steps at the interface of 4 degrees off (100) towards (111)A misoriented InP substr ates and also attributed to a thermally activated phenomenon. Furtherm ore, the results of Transmission Electron Microscopy (TEM) and X-Ray D iffraction (XRD) reveal that the lateral composition modulation acts a s a strain relieving mechanism that accommodates the tensile mismatch between the InAlAs buffer and the substrate. (C) 1997 Elsevier Science Ltd.