Relationship between classical and quantum lifetimes in AlGaN/GaN heterostructures

Carrier transport in a set of AlGaN/GaN heterostructures from different sources with a range of carrier densities and mobilities has been investigated at low temperature and high magnetic fields. The Shubnikov-de Haas oscillations have been analysed to extract the quantum scattering lifetime, τ q , and this is compared with the classical transport lifetime, τ t , derived from the low-field mobility. The relationship between these parameters has been observed to depend systematically on the low-field mobility of the samples studied, and indicates that higher-mobility samples suffer less scattering from centres close to the two-dimensional conducting channel.