AVS 52nd International Symposium
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM2
High Resolution Angle Resolved Photoemission Study of the Electronic Structure of InN(0001)

Friday, November 4, 2005, 8:40 am, Room 203

Session: Electronic Structure of Surfaces
Presenter: L. Colakerol, Boston University
Authors: L. Colakerol, Boston University
L. Plucinski, Boston University
S. Wang, Boston University
H.K. Jeong, Boston University
K.E. Smith, Boston University
P. Chen, Boston University
T.D. Moustakas, Boston University
Correspondent: Click to Email
We report a study of the surface and bulk electronic structure of InN(0001) thin films using high resolution synchrotron radiation excited angle-resolved photoemission (ARPES).@footnote 1@ The InN thin films were grown by plasma-assisted molecular beam epitaxy on c-plane sapphire, and transferred in air to the synchrotron. Samples were cleaned both by annealing in UHV and by cycles of nitrogen ion bombardment followed by UHV annealing. Sharp 1 x 1 hexagonal LEED patterns were observed from the films following either cleaning procedure. Aside from the expected bulk valence band states, we have observed a series of unusual states near E@sub F@, in the bulk band gap, for a narrow range of excitation energies and band momenta. These states are free electron-like, with parabolic dispersion around the surface Brillouin zone center. The number of states observed is a function of annealing temperature, and these states are likely the result of segregation of In metal to the surface. Up to four individual states are observed, and we associate them with quantum well states due to an In metal overlayer. The states are insensitive to contamination by exposure to 1000 L H@sub 2@, and are not related to intrinsic surface states. Our results are discussed in the context of both the known surface electronic structure of GaN (0001),@footnote 2@ and of charge accumulation at InAs surfaces.@footnote 3@ @FootnoteText@ @footnote 1@ Supported in part by the NSF DMR-0311792, by U.S. ARO 40126-PH, and by U.S. AFOSR. Our spectrometer system is funded by U.S. ARO DAAD19-01-1-0364. Experiments performed at the NSLS which is supported by the U.S. DOE, Divisions of Materials and Chemical Sciences.@footnote 2@ Y.C. Chao, C.B. Stagarescu, J. Downes, P. Ryan, K.E. Smith, D. Hanser, and R.F. Davis, Phys. Rev. B 59, 15586 (1998).@footnote 3@ L.O. Olsson, C.B.M. Andersson, M.C. Haakansson, J. Kanski, L. Ilver, and U.O. Karlsson, Phys. Rev. Lett. 76, 3626 (1996).