Two-dimensional electronic transport in AlGaN/GaN heterostructures

The mobility of a two-dimensional electron gas confined at the AlGaN/GaN interface has been calculated. Maximum low-temperature mobilities close to 10⁶ cm²/Vs are predicted for optimized modulation doped heterostructures. The calculations indicate that the much lower electron mobility observed in currently available structures can be explained by scattering from unintentionally incorporated charged defects and/or donors. It has been also found that incorporation of 200 Å thick spacer maximizes the electrical conductivity in high purity GaN quantum wells.