Microwave-aided transport measurements on high-density two-dimensional electron systems confined at AlGaN/GaN heterointerfaces

We present microwave‐aided magnetotransport measurements on high‐density two‐dimensional electron gas (2DEG) systems confined at AlGaN/GaN heterointerfaces. We show that the modulated patterns of Shubnikov‐de Haas (SdH) oscillations which are due to higher‐subband occupation can be drastically enhanced by employing the microwave modulation technique, allowing direct experimental observation and analysis. In addition, the SdH oscillations can be observed at a much lower magnetic field. Thus we provide a powerful way to study high‐density 2DEG systems which possesses higher resolution and enhanced pattern, does not alter carrier concentrations, and merely requires direct data analysis without numerical artifacts compared with conventional measurements. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)