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Todd Karin

Todd Karin

We need viable green technologies to reduce global carbon emissions, but the physical materials that make up these technologies are not fully understood. The III-V semiconductor material system takes a prominent place in the arsenal of light-harvesting and light-producing technologies: it is used in commercial LEDs and in the highest efficiency solar cells. While III-V materials are well studied, there are still questions surrounding the optical and electronic properties of common crystal defects.

In semiconductor devices, defects play a central role in determining device operation and efficiency. Even small number of defects can dominate semiconductor properties. For example, solar cells are made by incorporating impurity atoms at a concentration of one in a million host atoms. Unwanted defects on the other hand, even at low concentrations, can interfere with device function.

I develop new tools to study crystal defects in the pure III-V material system, with the goal of applying these techniques to study novel or dirtier materials. A fuller understanding of defects in III-V materials will be crucial for designing next-generation green technologies.

Advisor: Kai-Mei Fu, Physics