Reminder: MSE Ph.D. Dissertation Defense: Angie C. Lin (Tues Nov 8, 10am, CISX Auditorium)
angiel at stanford.edu
Mon Nov 7 14:23:38 PST 2011
University Ph.D. Dissertation Defense
Department of Materials Science and Engineering
All-epitaxial orientation-patterned III-V semiconductors for nonlinear optics
Angie C. Lin
Advisor: Professor James S. Harris
Tuesday, November 8, 2011
10 am (refreshments at 9:45 am)
CIS-X Auditorium, Paul G. Allen building
Applications such as airborne countermeasures, chemical spectroscopy, and imaging require high-power, compact, and tunable light sources in the infrared (IR) and Terahertz (THz) spectral ranges. While laser sources exist at certain frequencies in this range, they are bulky and require low temperature operation. Another solution is to generate the desired IR and THz frequencies through nonlinear optical frequency conversion in orientation-patterned III-V semiconductors, from readily available high-power lasers in the near-IR. Achieving high conversion efficiencies requires the optical signals to be quasi-phase-matched (QPM) inside the semiconductor.
Orientation-patterning is an all-epitaxial technique in which we fabricate QPM semiconductor structures by the following steps: growth by molecular beam epitaxy (MBE), lithography, etching, and regrowth by MBE. Previous work on orientation-patterned GaAs has led to demonstration of a variety of nonlinear optical devices; however, there is a push to develop orientation-patterned GaP (OP-GaP) to overcome inherent material limitations in GaAs. This thesis work has been focused on the development of OP-GaP, including MBE growth and characterization of GaP films on Si and processing of OP-GaP structures. Improvements in material quality have been made through the course of studying the nucleation and growth conditions of GaP on Si to control the formation and annihilation of antiphase domain defects. Understanding the growth of GaP on Si has not only enabled the development of OP-GaP as a platform for nonlinear optical devices, but also for III-V epitaxial mirrors on Si substrates for optical coatings.
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