X-ray reciprocal lattice mapping and photoluminescence of GaN/GaAlN Multiple Quantum Wells; strain induced phenomena.
R. Langer, J Simon, O. Konovalov, N. Pelekanos, A. Barski
CEA/Grenoble, Département de Recherche Fondamentale sur la Matière Condensée/SP2M
M. Leszczynski
High Pressure Research Center
This article was received on Tuesday, July 21, 1998 and
accepted on Monday, October 26, 1998. Abstract
Structural
properties of GaN/GaAlN multiple quantum wells (MQW) grown by nitrogen plasma
assisted MBE on MOCVD-grown GaN/sapphire (GaN pseudosubstrates) have been
characterised by X-ray reciprocal lattice mapping to determine the strain and
composition of ternary alloys. The results clearly demonstrate that the
barriers of GaAlN with up to 17% of aluminium content grown by plasma assisted
MBE on GaN are fully strained. Optical properties have been characterised by
low temperature photoluminescence. Photoluminescence emission peaks
corresponding to the GaN/GaAlN MQW structures revealed strong red-shift with
respect to the GaN energy gap. This can be explained by a strong internal
electric field present in the QW's which is attributed to a transfer of
piezoelectric field due to Fermi-level alignment.
