Plasma‐assisted MBE growth of (11 $ \bar 2 $ 2)‐oriented GaN/AlN quantum wells on m‐sapphire

We report on the plasma‐assisted molecular‐beam epitaxy growth of two‐dimensional (11 $ \bar 2 $ 2)‐oriented AlN, GaN and GaN/AlN multiple quantum well (MQW) structures on (1 $ \bar 1 $ 00) m ‐plane sapphire. Moderate N‐rich conditions enable to synthesize AlN(11 $ \bar 2 $ 2) directly on m ‐sapphire, with inplane epitaxial relationships [11 $ \bar 2 $ $ \bar 3 $ ] AlN || [0001] sapphire and [1 $ \bar 1 $ 00] AlN || [11 $ \bar 2 $ 2] sapphire . In the case of GaN a Ga‐excess of one monolayer is necessary to achieve two‐dimensional growth of GaN(11 $ \bar 2 $ 2). Applying the adequate growth conditions, we demonstrate the synthesis of (11 $ \bar 2 $ 2)‐oriented GaN/AlN MQW structures. The reduction of the luminescence red shift and of the luminescence decay time compared to standard polar structures confirms the quantum confined Stark effect attenuation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)