Date of Award
Master of Science
Department of Engineering Physics
Robert L. Hengehold, PhD
The purpose of this research was to determine the quality of AIGaN samples with various mole fractions of aluminum doped with silicon. The samples utilized for this study were composed of an AIN buffer layer sandwiched between the sapphire substrate and AIGaN epilayer grown by molecular beam epitaxy (MBE). Cathodoluminescence (CL) and photoluminescence (PL) were employed to determine the mole fraction of aluminum in each sample. These techniques also gave insight into the material's nonuniformity, defects, and impurities. CL was run at 4 different beam energies (2,5,10, & 15 keV) with four different currents (1,10,50, & 90 µA) for the GaN standard sample, AIGaN samples, and AIN buffer layers in the AIGaN samples. PL was also used to try to distinguish between certain transitions. Optical absorption was performed to obtain band gap energies to compare to those found in CL and PL. The finding of this study was that AIGaN grown by MBE is a good method for aluminum mole fractions of less than 0.30. Above this mole fraction, either a different growth technique or modifications to the MBE growth cycle are necessary to obtain quality material for semiconductor devices with applications in plume detection and threat warning systems.
DTIC Accession Number
McFall, Judith L., "Optical Investigation of Molecular Beam Epitaxy AlxGa1-xN to Determine Material Quality" (2000). Theses and Dissertations. 4828.