Nanoscience and Microsystems ETDs

Publication Date

Fall 12-17-2022

Abstract

Monolithic semiconductor lasers including edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs) fail to realize simultaneous achievement of both high-power high-quality beams due to intrinsic limitations of their resonant cavity. Photonic crystal surface emitting lasers (PCSELs) address these structural limitations through employment of a two-dimensional photonic crystal (PC) cavity that creates feedback at a single wavelength for laterally scalable devices. This function of the PC allows PCSELs to power scale with area while maintaining single-mode emission required for diffraction-limited beams. In this way, PCSELs fulfill an industry demand for high-power high-quality lasing from a single chip.

Early PCSELs were fabricated by way of wafer fusion where two wafers, the first containing the active layer and the second containing the PC, are joined together via heat treatment in a liquid phase epitaxy furnace. This technique produces a high density of light absorbing defects at the bonded interface. Modern PCSEL fabrication forgoes wafer bonding in favor of processes that maintain crystalline order throughout the entire structure. This work demonstrates PCSEL fabrication by epitaxial regrowth and single- epitaxy methods to illustrate their respective advantages and engineering challenges. While specific properties of epitaxial regrowth are beneficial for total output power, a single-epitaxy process simplifies fabrication and provides a more scalable and wavelength versatile platform. PCSELs with InGaAs multiple-quantum-well (MQW) active regions are constructed by molecular beam epitaxy (MBE) using both regrowth and single-epitaxy methods. Total output power of epitaxially regrown PCSELs is dramatically improved by implementation of a flip-chip bonding process and a metal- organic chemical vapor deposition (MOCVD) regrowth step. By affecting stable large- area coherent lasing, the fabricated PCSELs described in this work address the shortcomings presented by traditional EEL and VCSEL devices. Ultimately, both epitaxial regrowth and single-epitaxy PCSEL fabrication present advantages to satisfy different ends and are critical for future PCSEL development.

Keywords

Semiconductor, Laser, Photonic Crystal, Regrowth, Quantum, Optoelectronic

Document Type

Dissertation

Language

English

Degree Name

Nanoscience and Microsystems

Level of Degree

Doctoral

Department Name

Nanoscience and Microsystems

First Committee Member (Chair)

Ganesh Balakrishnan

Second Committee Member

Francesca Cavallo

Third Committee Member

Sang M. Han

Fourth Committee Member

Raktim Sarma

Available for download on Tuesday, December 17, 2024

Share

COinS