Details

Schwingungs- und elektronenspektroskopische Untersuchungen an reinen und wasserstoffbedeckten III-Nitridoberflächen - Vibrational and electronic spectroscopy of clean and hydrogen-covered III-nitride surfaces

by Grabowski, Stefan Peter

Abstract (Summary)
In this thesis clean GaN{0001} as well as AlGaN(0001) surfaces were characterized by high-resolution electron energy-loss spectroscopy (HREELS) and electron spectroscopic means. Moreover, the interaction of hydrogen with GaN{0001} surfaces of both polarities was investigated. At clean GaN surfaces the vibrational and electronic properties were determined, surface cleaning procedures and thermal decomposition were examined. By means of HREELS the energy of the Fuchs-Kliewer (FK)-phonon was determined as 86.8 meV. At Ga-polar surfaces a gap state at 2.7 eV was found. Atomic hydrogen was found to bind to both N and Ga. Deuteration of the surface delivered clear evidence for this behaviour and, thus, resolved a discrepancy published in the literature. Photoemission measurements confirmed this finding. The properties of AlGaN surfaces were investigated as a function of their composition. Over the whole composition range no evidence for a negative electron affinity was found. The FK phonons of AlGaN show a one-mode behaviour.
Bibliographical Information:

Advisor:Prof. Dr. W. Mönch; Prof. Dr. R. Courths

School:Universität Duisburg-Essen, Standort Essen

School Location:Germany

Source Type:Master's Thesis

Keywords:physik astronomie universitaet duisburg essen

ISBN:

Date of Publication:05/23/2003

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