MULTISUBBAND HOT-ELECTRON TRANSPORT IN GAN-BASED QUANTUM-WELLS

A simple rigorous analytical theory of two-dimensional (2D) nonequilib rium electrons occupying an arbitrary number of subbands in a quantum well is developed. The electric-field dependence of electron mobility and the average kinetic energy for AlN/GaN quantum wells are presented . At temperatures below 200 K the electron mobility is controlled main ly by the acoustic phonon scattering and it is a nonmonotonous functio n of the electric field, which has a maximum. At room and higher tempe ratures the interaction with both acoustic and polar optical phonons d etermine the hot-electron mobility and it depends very weakly on the e lectric field. Both the mobility and average energy of 2D electrons ar e smaller than that for three-dimensional (3D) electrons in the bulk s emiconductor. Our theory provides a self-consistent transition from th e 2D to the 3D regime of electron transport with increasing electric f ield accompanied by the occupation of an increasingly large number of subbands by the electrons. (C) 1998 American Institute of Physics. [S0 003-6951(98)03943-6].