Relationship between classical and quantum lifetimes in AlGaN/GaN heterostructures

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