| Author(s): |
Seong-Eun Park; Joseph J. Kopanski; Youn-Seon Kang; Lawrence H. Robins; Hyun-Keel Shin; |
| Title: |
Determination of surface barrier height and surface state density in GaN films grown on sapphire substrates |
| Published: |
March 24, 2005 |
| Abstract: |
Photoreflectance (PR) modulation spectroscopy was performed to investigate surface properties of GaN films grown on sapphire substrates. From the period of the Franz-Keldysh oscillations, the surface electric field across the GaN space charge region was found to be (197.3 '' 11.4) kV/cm, which corresponds to a surface state density of 1.0 x 10e12 cm^-2. A surface barrier height (SBH) of 0.71 eV was determined by fitting the dependence of the PR intensities on pump beam power density. We suggest that a deep level is formed at 2.68 eV above the GaN valence band edge due to the large density of surface states. |
| Proceedings: |
MRS Electronic Proceedings |
| Pages: |
pp. E3.2.1 - E3.2.6 |
| Location: |
Boston, MA |
| Dates: |
November 29-December 3, 2004 |
| Keywords: |
GaN;Photoreflectance;Surface electronic properties |
| Research Areas: |
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