Atomic and electronic structure of the cleaved non-polar 6H-SiC(11-20) and GaN(1-100) surfaces

Abstract

The title of this Ph.D. thesis is Atomic and electronic structure of the cleaved non-polar 6H-SiC(11-20) and GaN(1-100) surfaces . It shows the results of a combined experimental and theoretical study which has been done at the IV. Physikalischen Institut der Georg-August Universität Göttingen (Germany) in cooperation with the Università di Modena und Reggio Emilia (Italy) and the National Research Center (CNR) in Parma (Italy). The goal of this study was to investigate the physical properties of the cleaved non-polar silicon-carbide (6H-SiC) and gallium-nitride (GaN) semiconductor surfaces which hold a high potentiality for light emitting dioes and laser diodes operating with high efficiency in the green wavelength range. The main goal is to close the so-called green-gap of nitride-based light diodes. In view of the promising industrial applications and because of the lack of experimental measurements on the clean non-polar 6H-SiC and GaN surfaces, we decided to investigate these surfaces by Cross Section Scanning Tunneling Microscopy and -Spectroscopy (X-STM/STS). This Ph. D. thesis contains the first published experimental data on the cleaved non-polar 6H-SiC(11-20) and GaN(1-100) surfaces. The results on the SiC system were published in Physical Review B (75, 165312, 2007) and the results on the GaN system were accepted for publication in the same scientific journal (2009).