1. For a review of the physical properties of the III-V nitrides see: S. Strite and H. Morkoç,J. Vac. Sci. Technol. B 10,1237 (1992).
2. For a review of the III-V nitrides as a device technology see: H. Morkoç, S. Strite, G.B. Gao, M.E. Lin, B. Sverdlov and M. Burns,JAP Rev. pending; for a review of wide-bandgap semiconductors see:Proc. Seventh Trieste ICTP-IUPAP Semiconductor Symposium, (1992), ed. C.G. Van de Walle,Physica B 185 (1993).
3. The method is descibed in detail by R.W. Grant, E.A. Kraut, J.R. Waldrop and S.P. Kowalczyk,Heterojunction Band Discontinuities, ed. F. Capasso and G. Margaritondo (Amsterdam: North-Holland Physics Publishing, 1987) ch. 4.
4. Values from this current work were reportedin Appl. Phys. Lett. 65, 610 (1994).
5. M.E. Lin, B. Sverdlov, G.L. Zhou and H. Morkoç,Appl. Phys. Lett. 62, 3479 (1993).