HiLASIANS Alexander V. Bulgakov (team leader of Nanomaterials), Nadezhda M. Bulgakova (head of Scientific Laser Applications), Jiří Beránek (Ph.D. student, Laser Matter Interaction), and Martin Zukerstein (post-doc, Laser Material Processing) are the co-authors of a new study titled Ultrafast Infrared Laser Crystallization of Amorphous Ge Films on Glass Substrates.
It was published in the Micromachines journal, in collaboration with researchers from Novosibirsk State University and the Russian Academy of Sciences: Yuzhu Cheng, Ilya A. Milekhin, Alexander A. Popov, and Vladimir A. Volodin.
Amorphous germanium films on non-refractory glass substrates were annealed by ultrashort near-infrared (1030 nm, 1.4 ps) and mid-infrared (1500 nm, 70 fs) laser pulses. Crystallization of germanium irradiated at a laser energy density (fluence) range from 25 to 400 mJ/cm2 under single-shot and multishot conditions was investigated using Raman spectroscopy. The dependence of the fraction of the crystalline phase on the fluence was obtained for picosecond and femtosecond laser annealing. The regimes of almost complete crystallization of germanium films over the entire thickness were obtained (from the analysis of Raman spectra with excitation of 785 nm laser). The possibility of scanning laser processing is shown, which can be used to create films of micro- and nanocrystalline germanium on flexible substrates.