Events Calendar
From Materials Engineering to Device Applications: Testing Our Understanding of Nature
Thursday November 5, 2015
11:00 am
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Presenter: | Professor Sang Han, Departments of Chemical & Nuclear Engineering and Electrical & Computer Engineering |
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Series: | OSE Seminars | |
Abstract: | My research group has worked on epitaxial growth of high-quality germanium on silicon for a variety of advanced applications, including virtual substrates for integrating III-V multijunction solar cells, high-mobility transistors, and quantum computers. In this presentation, I will discuss the importance of understanding (1) the surface physics of growth precursors on silicon vs. on masking template for selective epitaxial growth and (2) the impact of templates on crystalline defects, film stress, and material quality. In a particular case of uniformly applied 2D array of compressive stress, I will further describe how such stress field can cause compositional variation in silicon-germanium alloys to form germanium quantum dots without needing additional Stranski-Krastanov-type growth. As an ultimate test of our cumulative understanding, we successfully integrated III-V films on silicon for photovoltaic applications, and fabricated and characterized high-mobility transistors on wafer-scale, engineered germanium-on-silicon substrates. I will present the details of our findings and their implications in creating unique engineering devices. | |
Location: | Room 101, Center for High Tech Materials | |