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Bulk and Surface Electronic Structure of GaN Measured Using Angle-Resolved Photoemission, Soft X-ray Emission and Soft X-ray Absorption

Published online by Cambridge University Press:  10 February 2011

Kevin E. Smith ,
Sarnjeet S Dhesi ,
Laurent-C. Duda ,
Cristian B Stagarescu ,
J. H. Guo ,
Joseph Nordgren ,
Raj Singh  and
Theodore D Moustakas
Kevin E. Smith
Affiliation:
Department of Physics, Boston University, Boston, MA 02215 author to whom correspondence should be addressed. Electronicmail: ksmith@bu.edu
Sarnjeet S Dhesi
Affiliation:
Department of Physics, Boston University, Boston, MA 02215
Laurent-C. Duda
Affiliation:
Department of Physics, Boston University, Boston, MA 02215
Cristian B Stagarescu
Affiliation:
Department of Physics, Boston University, Boston, MA 02215 On leave from the Institute of Microtechnology, Bucharest, Romania.
J. H. Guo
Affiliation:
Department of Physics, Uppsala University, Uppsala, Sweden
Joseph Nordgren
Affiliation:
Department of Physics, Uppsala University, Uppsala, Sweden
Raj Singh
Affiliation:
Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215.
Theodore D Moustakas
Affiliation:
Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215.
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Abstract

The electronic structure of thin film wurtzite GaN has been studied using a combination of angle resolved photoemission, soft x-ray absorption and soft x-ray emission spectroscopies. We have measured the bulk valence and conduction band partial density of states by recording Ga L- and N K- x-ray emission and absorption spectra. We compare the x-ray spectra to a recent ab initio calculation and find good overall agreement. The x-ray emission spectra reveal that the top of the valence band is dominated by N 2p states, while the x-ray absorption spectra show the bottom of the conduction band as a mixture of Ga 4s and N 2p states, again in good agreement with theory. However, due to strong dipole selection rules we can also identify weak hybridization between Ga 4s- and N 2p-states in the valence band. Furthermore, a component to the N K-emission appears at approximately 19.5 eV below the valence band maximum and can be identified as due to hybridization between N 2p and Ga 3d states. We report preliminary results of a study of the full dispersion of the bulk valence band states along high symmetry directions of the bulk Brillouin zone as measured using angle resolved photoemission. Finally, we tentatively identify a non-dispersive state at the top of the valence band in parts of the Brillouin zone as a surface state.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 449: Symposium N – III-V Nitrides , 1996 , 787
Copyright
Copyright © Materials Research Society 1997

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References

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