Polarization field control in GaInN quantum well heterostructures on semipolar growth surfaces

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The objective of this project is to investigate the epitaxial growth process of GaN-based materials on semipolar GaN surfaces for long wavelength light emitting diodes and lasers using metal organic vapor phase epitaxy (MOVPE). One of the main problems that limits the performance of optoelectronic devices on conventional c-plane GaN are the strong polarization effects that occur at the heterointerfaces (e.g. InGaN-GaN, AlGaNGaN). Growth on semipolar surfaces inclined to the c-plane will allow a significant reduction of the polarization fields. In the second phase of the project, the growth of In-AlGaN heterostructures on low defect density semipolar bulk GaN substrates will be investigated. Based on previous results we will focus on GaN with (1122) and (2021) orientations, since they provide excellent indium incorporation efficiencies and overall good morphologies. Another goal of the project focuses on the development of fabrication processes for non- and semipolar LED and laser devices. This includes investigation of ohmic contacts and further improvement of cleaving and dry etching techniques to create laser mirrors. Finally, we will fabricate and characterize LEDs, optically pumped laser heterostructures and current-injection laser diodes. Furthermore, we will explore fundamental physical properties of InGaN quantum well LEDs and lasers on semipolar GaN, e.g. the recombination dynamics, quantification of the polarization fields, the polarization state of light emitted by semipolar LEDs, and the polarization characteristics of semipolar waveguides.