Date of Award
Doctor of Philosophy (PhD)
Department of Engineering Physics
Yung Kee Yeo, PhD
Deep Level Transient Spectroscopy (DLTS) was used to characterize the band offsets and deep levels in MBE grown GaSb-based semiconductors that are used in 2-4 µm laser diode structures. One of several deep level traps found in AlxGa1-xAsySb1-y (x=0, 0.5, 0.6, 1.0) is a GaSb double acceptor trap. Progress is also made in establishing the model for the DX center in this material. The degree of compensation of the donor related DX center by GaSb affect where donors are situated, giving preference to one configuration over the many other possible configurations. One minority trap 320 meV below the conduction band, and six hole traps 24, 76, 108, 122, 224, and 276 meV above the valence band were found in the Ga0.85In0.15As0.12Sb0.88 using DLTS measurements. It is believed that the minority trap level at 320 meV and the hole trap level at 276 meV originate from the same trap, making it the most efficient non-radiative recombination center. Extrapolating a series of quantum well emission energies measured by DLTS (based on Boltzmann's approximation) to a point where the approximation is valid, results in a valence band offset of 0.52 eV between Ga0.81In0.19As0.12Sb0.88 and Al0.9Ga0.1AsSb lattice matched to GaSb.
DTIC Accession Number
Johnstone, Daniel K., "Electrical Characterization of GaSb Based Semiconductors for 2-4 micrometers Diode Laser Applications" (1996). Theses and Dissertations. 6062.