This paper presents simulated DC characteristics, using the commercially available software DESSIS, of an AlGaN/GaN HEMT, along with corroborating experimental measurements for validation, providing a framework for future optimization. The 2D simulations are reported using theoretically predicted values of polarization charges along with surface traps in the source-gate and gate-drain access regions. The necessity of including hydrodynamic (energy balance) transport, quantization models for accurate simulations is demonstrated along with insight into the inclusion of a lumped thermal resistance which is extended to non-isothermal simulations. (c) 2006 Elsevier Ltd. All rights reserved.