SMALL VALENCE-BAND OFFSETS AT GAN INGAN HETEROJUNCTIONS/

The band discontinuities between GaN and InN, as well as InGaN alloys, are key parameters for the design of nitride-based light emitters. Va lues reported to date are subject to large uncertainties due to strain effects at this highly mismatched interface. We have investigated the band lineups using first-principles calculations with explicit inclus ion of strains and atomic relaxations at the interface. We find that t he ''natural'' valence-band offset between unstrained InN and GaN is 0 .3 eV. Prescriptions are given, including the band shifts, due to stra ins at a pseudomorphic interface. (C) 1997 American Institute of Physi cs.