Date of Graduation
Master of Science in Microelectronics-Photonics (MS)
Gregory J. Salamo
This work aimed to explore nanostructure configuration by growing multiple layers of strained InGaAs on GaAs high index surface. The knowledge learned would help to achieve a comprehensive picture of strain-driven nanostructure evolution. Ordered arrays of InGaAs quantum dots were demonstrated on GaAs(311)B. The ordering patterns depended on the thickness of GaAs interlayer between InGaAs Quantum Dots (QDs). With an increased interfacial thickness, a transition from two dimensional (2D) lateral ordering to 1D dot chains was observed. InGaAs growth on GaAs(311)A and GaAs(331)A ended up with 1D quantum wires (QWRs). Straight InGaAs QWRs were uniformly distributed across the surfaces owing to multiple depositions. Strain-field interaction among multilayer, high temperature enhanced surface mobility, and surface stability were the consequential explanation. Reducing the thickness of GaAs(210) interlayer spacer resulted in a transition from InGaAs quantum dash to arrow-like structures. Both 1D and 2D lateral ordering of InGaAs/GaAs(210) were observed by adjusting InGaAs coverage. GaAs(731)A is a surface lying inside of the stereographic triangle. Stacking multilayer of InGaAs resulted in a highly non-uniform QD spatial distribution. GaAs(731) was revealed a candidate substrate for the growth of QD clusters. Bamboo-like nanostructures emerged upon InGaAs coverage variation; QDs aligned in clusters separated the "bamboo" into sections.
Xie, Yanze, "Morphology of InGaAs Multilayer Nanostructure on GaAs High-Index Surfaces" (2009). Theses and Dissertations. 46.