Mohammed Abdullah Abo Alreesh

PhD student

My name is Mohammed Abo Alreesh and I am currently a graduate student at the Materials Department, Universirty of California Snata Barbra (UCSB) in the United States. I studied physics -as an under graduate- initially at KFUMP and completed my bachelor degree at Umm Al-Qura University with first honor. In 2012, I became a lecturer at the physics dept. at King Saud University. When I received a PhD scholarship, I joined the materials dept. at UCSB in 2014. UCSB is one of the leading universities in the Materials and Solid State research with main interest in Light Emitting Diode LED, Laser Diode LD, and Power electronics. My research focuses on growing Gallium Nitride (GaN) substrates, a wide band semiconductor that is used in LED, LD, and Power electronics. These devices are usually grown on heterogenous substrates which initiate stress and defects and as a result reduces their efficiency and the lifetime. GaN substrates grown by Hydride vapor phase epitaxy (HVPE) are commercially available but are expensive and contains significant defects. Thus, other methods, such as Amonothermal and Sodium flux, were developed to enhance the structural quality. The Sodium flux method – my research method- was developed by a research group led by Prof. Mori from Osaka University. They have shown considerable potential with low defects and high growth rate GaN substrates. At UCSB, we are trying to develop this method further as the demand for GaN substrates has increased especially for GaN based power electronics and Laser Diodes. my research focus on Increasing the growth rate, reducing the impurities and the structural defects, and exploring different fluxes other than Sodium. By the end of my PhD journey, I hope that I can grow GaN substrates with high structural quality, less impurities, and more reproducibility. If these goals are achived, they can have a significant impact on the lighting and power electronic industry.

  • Von Dollen, P., Pimputkar, S., Alreesh, M., Albrithen, H., Suihkonen, S., Nakamura, S., Speck, J. (2016). A new system for sodium flux growth of bulk GaN. Part I: System development. Journal of Crystal Growth, 456, 58-66
  • Von Dollen, P., Pimputkar, S., Alreesh, M., Nakamura, S., Speck, J. (2016). A new system for sodium flux growth of bulk GaN. Part II: in situ investigation of growth. Journal of Crystal Growth, 456, 67-72