There is an understanding of surface photovoltage (SPV) behavior for GaN, yet little is known about the SPV behavior for AlGaN. In this work, a Kelvin probe was used to measure the SPV for p-type AlGaN. Very slow SPV transients were found in AlGaN, which could not be explained with a simple thermionic model. A possible explanation of this behavior is the segregation of impurities to the surface, which causes significant reduction of the depletion region width (down to 2 nm), with carrier tunneling and hopping becoming the dominant mechanisms responsible for the SPV transients. To verify this assumption, the near-surface defective region (about 40 nm) has been removed through the ICP-RIE process. After the etching, the SPV transients became fast and increased in magnitude by about 0.6 eV. By using the thermionic model, band bending was estimated to be -1 eV.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-4883 |
| Date | 01 January 2015 |
| Creators | Phumisithikul, Karen L |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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