Polarization-engineering in group III-nitride heterostructures: New opportunities for device design

Abstract

The role of spontaneous and piezoelectric polarization in III–V nitride heterostructure devices is discussed. Problems as well as opportunities in incorporating polarization in abrupt and graded heterojunctions composed of binary, ternary, and quaternary nitrides are outlined.! 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Introduction Spontaneous polarization exists along the (0001) (metal-polar) and ð0001Þ (N-polar) directions of wurtzite III–V nitride semiconductor crystals. Strain-induced piezoelectric polarization can either add to, or subtract from the spontaneous polarization in heterostruc