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Formation mechanism of self-assembled polarization-dependent periodic nanostructures in β-Ga2O3
Author(s): Y. Nakanishi; Y. Shimotsuma; M. Sakakura; M. Shimizu; K. Miura
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Paper Abstract

We have successfully observed self-assembled periodic nanostructures inside Si single crystal and GaP crystal, by the femtosecond double-pulse irradiation. These results experimentally indicate that the self-assembly of the periodic nanostructures inside semiconductors triggered by ultrashort pulses irradiation are possibly associated with a direct or an indirect band gap. More recently we have also empirically classified the photoinduced bulk nanogratings into the following three types: (1) structural deficiency, (2) compressed structure, (3) partial crystallization. We have still a big question about what material properties are involved in the bulk nanograting structure formation. In this study, to expand the selectivity of the material for bulk nanograting formation, we have employed β-Ga2O3 crystals (indirect bandgap Eg ~ 4.8 eV) as a sample for femtosecond laser irradiation. The nanograting structure inside β-Ga2O3 crystal was aligned perpendicular to the laser polarization direction. Such phenomenon is similar to the nanograting in SiO2 glass (Eg ~ 9 eV). Moreover, to clarify the band structure, we have also investigate the photoinduced structure in Sn doped β-Ga2O3 crystals, which exhibit direct bandgap according to the first principle calculation.

Paper Details

Date Published: 19 February 2018
PDF: 7 pages
Proc. SPIE 10520, Laser-based Micro- and Nanoprocessing XII, 105201J (19 February 2018); doi: 10.1117/12.2288276
Show Author Affiliations
Y. Nakanishi, Kyoto Univ. (Japan)
Y. Shimotsuma, Kyoto Univ. (Japan)
M. Sakakura, Kyoto Univ. (Japan)
M. Shimizu, Kyoto Univ. (Japan)
K. Miura, Kyoto Univ. (Japan)


Published in SPIE Proceedings Vol. 10520:
Laser-based Micro- and Nanoprocessing XII
Udo Klotzbach; Kunihiko Washio; Rainer Kling, Editor(s)

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