MIJ-NSR Vol. 2, Art. 14, A. Sohmer et al.

GaInN/GaN-Heterostructures and Quantum Wells Grown by Metalorganic Vapor-Phase Epitaxy

A. Sohmer, J. Off, H. Bolay, V. Härle, V. Syganow, Jin Seo Im, V. Wagner, F. Adler, Andreas Hangleiter , A. Dörnen, Ferdinand Scholz
4. Physikalisches Institut, Universität Stuttgart

D. Brunner, O. Ambacher
Walter Schottky Institut, Technische Universität München

H. Lakner
Werkstoffe der Elektrotechnik, Gerhard-Mercator-Universität Duisburg

This invited article was received on Wednesday, May 7, 1997 and accepted on Tuesday, July 22, 1997.

Abstract

The dependence of the In-incorporation efficiency and the optical properties of MOVPE-grown GaInN/GaN-heterostructures on various growth parameters has been investigated. A significant improvement of the In-incorporation rate could be obtained by increasing the growth rate and reducing the H₂-partial pressure in the MOVPE reactor. However, GaInN layers with a high In-content typically show an additional low energy photoluminescence peak, whose distance to the band-edge increases with increasing In-content. For GaInN/GaN quantum wells with an In-content of approximately 12%, an increase of the well thickness is accompanied by a significant line broadening and a large increase of the Stokes shift between the emission peak and the band edge determined by photothermal deflection spectroscopy. With a further increase of the thickness of the GaInN layer, a second GaInN-correlated emission peak emerges. To elucidate the nature of these optical transitions, power-dependent as well as time-resolved photoluminescence measurements have been performed and compared to the results of scanning transmission electron microscopy.