Polarization induced 2D hole gas in GaN/AlGaN heterostructures

The generation of high density 2D hole gases is crucial for further progres s in the electronic and optoelectronic nitride devices. In this paper, we p resent systematic theoretical studies of Mg-doped GaN/AlGaN gated heterostr uctures and superlattices. Our calculations are based on a self-consistent solution of the multiband k.p Schrodinger and Poisson equation and reveal t hat the hole 2D sheet density is mainly determined by the polarization indu ced interface charges. For an aluminium concentration of 30%, the induced h ole density in the heterostructure can reach values up to 1.5 x 10(13) cm(- 2). In the GaN/AlGaN superlattices, the hole sheet density increases with t he superlattice period and saturates for a period of 40 nm at a value of 1. 5 x 10(13) cm(-2). (C) 2001 Elsevier Science B.V. All rights reserved.