MBE-grown long wavelength InGaAlAs/InP laser diodes

An attempt was made to achieve high-performance 1.55I m semiconductor laser diodes based on the InGaAlAs material system with solid-source molecular beam epitaxy (MBE) technology. The primary motivation for this attempt was the possibility for enhanced QW laser performance with large conduction band offsets provided by InGaAlAs which, furthermore, can be realized with toxic-gas-free solid-source MBE technology. In order to realize this goal, the technique of growing high-quality InGaAlAs with MBE was first established and the resulting InGaAlAs bulk and quantum well samples were extensively characterized by double-crystal xray diffraction, transmission and photoluminescence measurements. 1.55 pm graded-index separateconfinement strained multiple quantum well lasers were then designed, epitaxially grown, and fabricated into broad-area and ridge-waveguide devices. The resulting devices were characterized for their threshold currents and quantum efficiencies, and these were compared with other reported values obtained from different material systems and/or epitaxy techniques. In addition, in order to realize distributed-feedback (DFB) lasers that do not require any epitaxial regrowth, a novel ridge-waveguide DFB structure was proposed, analyzed, and fabricated with x-ray lithography. Finally, an assessment was made on the future of MBE-grown InGaAlAs lasers for the fiber-optic application. Thesis Supervisor: Clifton G. Fonstad Title: Professor of Electrical Engineering