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Virginia Commonwealth University

Theses and Dissertations

Kelvin probe

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Full-Text Articles in Physics

Surface Photovoltage Transients For P-Type Algan, Karen L. Phumisithikul Jan 2015

Surface Photovoltage Transients For P-Type Algan, Karen L. Phumisithikul

Theses and Dissertations

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 Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara May 2013

The Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara

Theses and Dissertations

The development of gallium nitride (GaN) light emitting devices has reached extraordinary echelons. As such, the characterization and analysis of the behavior of GaN materials is essential to the advancement of GaN technology. In this thesis, the effect of temperature on the optical and electrical properties of p-type GaN is investigated. The GaN samples used in this work were grown by various methods and studied by Kelvin probe and photoluminescence (PL) techniques. Specifically, the surface photovoltage (SPV) behavior and PL data were analyzed at different temperatures and illumination intensities. Using the SPV results, we show that p-type GaN exhibits n-type …