A. Sohmer1, J. Off1, H. Bolay1, V. Härle1, V. Syganow1, Jin Seo Im1, Volker Wagner1, F. Adler1, A. Hangleiter1, A. Dörnen1, Ferdinand Scholz1, Daniel Brunner2, O. Ambacher2, Hubert Lakner3
14. Physikalisches Institut, Universität Stuttgart, Germany
2Walter Schottky Institut, Technische Universität München, Germany
3Werkstoffe der Elektrotechnik, Gerhard-Mercator-Universität Duisburg, Germany
Tóm tắt
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.
