Nanoporous GaN and Its Application in Vertical-Cavity Surface-Emitting Lasers [electronic resource] = 氮化镓纳米孔洞及其在垂直腔面发射激光器中的应用.

9781088315057

Ann Arbor : ProQuest Dissertations & Theses, 2019.

1 online resource (249 p.)

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Wide bandgap III-nitrides - including (Al,Ga,In)-N and their alloys, have seen enormous success over the past three to four decades and have emerged as one of the most important classes of semiconductor materials. Today, light-emitting diodes (LEDs) and laser diodes (LDs) based on (Al,In,Ga)-N have been successfully commercialized and used in various sectors, such as general lighting, displays, optical storage and automotive headlighting, just to name a few. Progress in GaN vertical-cavity surface-emitting lasers (VCSELs) so far, however, is stifled by daunting challenges in building micro-cavity and achieving electrical injection. The main reason is the difficulty in the formation of planar distributed Bragg reflectors (DBRs) for the III-nitride material system. Most of the processes (epitaxy and fabrication) introduce major compromises in material quality and device design, causing a severe downgrade in device performance.In this thesis we will demonstrate the possibility of using nanoporous (NP) GaN to provide unprecedented tunability in refractive index and break the intrinsic limitations in physical properties of bulk III-nitride materials. Using NP GaN, we introduce a new freedom in optical engineering of microcavity design without the constraints in epitaxy or complex fabrication. Record high reflectances (R > 99.5%) are demonstrated from epitaxial GaN DBRs that can be controllably fabricated. More importantly, the NP GaN-based reflector will give the III-nitride material system a design option of a conductive mirror to support vertical current injection that is crucially vital in attaining high performance VCSELs. With the NP DBR as the mirrors, optically pumped VCSELs and resonant-cavity LEDs (RC-LEDs) are demonstrated. While investigation is still ongoing on electrically injected VCSELs, substantial insight has been gained in VCSEL design principles, fabrication processes, electrical conductance and optical loss management through material characterization, electrical measurements and optical pumping techniques. Such VCSELs made with NP GaN mirrors are expected to reach unprecedented optical and electrical performances compared to its counterparts, providing a viable solution to the robust fabrication process and commercialization of GaN VCSELs.

Dissertations & Theses @ Yale University.

Books / Online / Dissertations & Theses

English

January 17, 2020

Thesis (Ph.D.)--Yale University, 2019.

Yale University. Electrical Engineering.