Nitride heterostructures: a system for high frequency electronics

A key property of the nitrides is the fact that they possess large spontaneous and piezoelectric polarization fields that allow a significant tailoring of the carrier dynamics and optical properties of nitride devices. In this paper, we review our recent studies of the nitride electronic devices. To assess the potential of this novel material class for modern device applications, we have performed multi-scale calculations that include ab initio density functional calculations, self-consistent multi-band k·p method, and ensamble Monte Carlo simulations. We find that the polarization induced charges at the interfaces produce two-dimensional electron and hole gases of high density up to 1013 cm−2. Our studies also reveal that the nitride based electronic devices have characteristics that predispose them for high power and high frequency applications. We demonstrate also that transistor characteristics are favorably influenced by the internal polarization induced electric fields.