DOI
https://doi.org/10.25772/5Z0Q-7T41
Defense Date
2017
Document Type
Thesis
Degree Name
Master of Science
Department
Electrical & Computer Engineering
First Advisor
Prof. Ümit Özgür, Ph.D.
Second Advisor
Prof. Hadis Morkoç, Ph.D.
Third Advisor
Prof. Vitaliy Avrutin, Ph.D.
Fourth Advisor
Prof. Michael Reshchikov, Ph.D.
Abstract
Efficient and robust blue InGaN multiple quantum well (MQW) light emitters have become ubiquitous; however, they still have unattained theoretical potential. It is widely accepted that “localization” of carriers due to indium fluctuations theoretically enhance their efficiency by moderating defect-associated nonradiative recombination. To help develop a complete understanding of localization effects on carrier dynamics, this thesis explores degree of localization in InGaN MQWs and its dependence on well thickness and number of wells, through temperature and power dependent photoluminescence measurements. Additionally, silicon-compatible, nontoxic, colloidally synthesizable 2-5 nm Ge1-xSnx alloy quantum-dots (QDs) are explored for potential visible to near-IR optoelectronic applications. While bulk Ge is an indirect gap material, QD confinement allows enhanced direct transitions, and alloying with Sn improves transition oscillator strengths. Temperature dependent steady-state and time-resolved photoluminescence reveal relaxation pathways involving bright/dark excitons and surface states in Ge1-xSnx QDs, showing their great potential for future use.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
12-14-2017
Included in
Electrical and Electronics Commons, Electromagnetics and Photonics Commons, Electronic Devices and Semiconductor Manufacturing Commons, Nanotechnology Fabrication Commons, Semiconductor and Optical Materials Commons