Crystallization of amorphous Ge thin films by nanosecond pulsed infrared laser

Korkut, Ceren
Crystalline semiconductors have superior optical and electrical properties to an amorphous structure; therefore, they are an essential part of photovoltaic applications. Pulsed laser irradiation is a cost-effective technique for the growth of polycrystalline germanium (pc-Ge). Laser processing also enables the production of local and wide-ranging nano-crystalline surface structures. Germanium has high carrier mobility, and Ge nanocrystals and microcrystals have a great potential in optoelectronics applications due to their optical properties. Laser parameters such as laser fluence and scan speed play an essential role in forming well-aligned and oriented pc-Ge domains. In this thesis, the nanosecond pulsed infrared laser parameters are investigated to form high-quality crystal structures. Besides, with the improvement of line focus scanning optics and different deposition techniques of Ge thin films, the dominant mechanism of crystallinity, and defect formation on the pc-Ge thin-films are studied. The laser crystallization is applied at room temperature in the air without additional heating substrates. The results of this study pave the way for producing crack-free and high-quality crystalline device-grade thin films, which may find applications in photovoltaics, and other thin film device applications.


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Citation Formats
C. Korkut, “Crystallization of amorphous Ge thin films by nanosecond pulsed infrared laser,” M.S. - Master of Science, Middle East Technical University, 2023.