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Wolfe, J.P. Martin, Gregory Allen 2011-05-07T13:06:19Z 2011-05-07T13:06:19Z 10000-01-01 1996 In this thesis the band alignments for wurtzite (0001) heterojunctions of AlN, GaN, and InN semiconductors are measured by x-ray photoemission spectroscopy. The bands alignments are all found to be Type I, and the valence-band discontinuities are found to be:(UNFORMATTED TABLE OR EQUATION FOLLOWS)$$\vbox{\halign{#\hfil&&\qquad #\hfil\cr &$\rm\Delta E\sb{v}$\ (eV)\cr\cr GaN on AlN &0.60 $\pm$ 0.24\cr AlN on GaN &0.57 $\pm$ 0.22\cr InN on GaN &0.93 $\pm$ 0.25\cr GaN on InN &0.59 $\pm$ 0.24\cr InN on AlN &1.71 $\pm$ 0.20\cr AlN on InN &1.32 $\pm$ 0.14\cr}}$$(TABLE/EQUATION ENDS) "Forward-backward growth asymmetries are found for InN$\vert$GaN and InN$\vert$AlN, and highlight the importance of lattice mismatch and its influence on band alignment. The dielectric midgap energy is affected by lattice mismatch strain to a small degree, but in the opposite direction as observed in the experimental results. The strain-induced piezoelectric effect would provide effects of the correct sign, but an explicit overlayer thickness dependence is not observed: The model of pseudomorphic strain is rejected for InN$\vert$GaN and InN$\vert$AlN as expected for the exceedingly large lattice mismatches, but pseudomorphic strain is not ruled out for GaN$\vert$AlN. Thermal mismatch strain is rejected as a significant factor. In general there is insufficient knowledge of strain conditions at heterojunctions of AlN, GaN, and InN to provide quantitative strain corrections to the observed valence-band discontinuities. A bonding model assumes the lattice mismatch is accommodated by dislocations and dangling bonds at the interface. The dangling bonds are viewed as dipole corrections to the ideal lattice-mismatched heterojunction, and the dipole model accounts for the signs and trends of the observed forward-backward asymmetries but the model values are an order of magnitude too small. Using rough approximations for strain and dangling bond corrections the ""bulk"" valence-band discontinuities are estimated as GaN$\vert$AlN $\approx$ 0.7 eV, InN$\vert$GaN $\approx$ 0.76 eV, and InN$\vert$AlN $\approx$ 1.51 eV. These values satisfy transitivity to well within experimental and estimation uncertainties. Tabulations of x-ray photoemission values for core-level energies with respect to valence band edges for wurtzite AlN, GaN, and InN are presented." Made available in DSpace on 2011-05-07T13:06:19Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712370.pdf: 3017177 bytes, checksum: 9c10564653b304e7b6542f762c06ed9c (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:50:13Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:22:55-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only 9780591199352 AAI9712370 (UMI)AAI9712370 http://hdl.handle.net/2142/21357 eng Copyright 1996 Martin, Gregory Allen Engineering, Electronics and Electrical Physics, Condensed Matter Engineering, Materials Science Semiconductor electronic band alignment at heterojunctions of wurtzite aluminum nitride, gallium nitride, and indium nitride text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.