Charge transport in low-dimensional nitride semiconductor heterostructures

Low-dimensional conducting channels in high electron mobility transistors ( HEMTs) based on AlGaN/GaN heterostructures have been modeled and the result s are described in this paper. The Schroedinger's equation and the Poisson' s equation have been solved self-consistently in order to obtain a relation ship between the sheet carrier density and the applied gate voltage. The re lationship is treated using a non-linear exponential fit that enables a mor e accurate analysis of the transport saturation region compared to other mo dels used hitherto. The current-voltage (I-V) characteristics have then bee n determined by a charge control analysis that utilizes the exponential cha rge-potential relationship. This identifies the saturation point of channel conduction without parameters extracted from experiments. The intrinsic no n-linearity of transport identified by the simulation explains why such dev ices do not have a singular channel "pinch-off" voltage. (C) 2001 Elsevier Science B.V. All rights reserved.