Highly oriented GeSe2 thin film growth using a facile low-vacuum annealing method

Abstract

Germanium diselenide (GeSe 2 ), a chalcogen-based wide-bandgap semiconductor, has recently attracted interest as a low-symmetry layered material with peculiar in-plane anisotropy. The excellent air stabil- ity of ultra-thin GeSe 2 flakes and impressive preliminary results for photodetection-based applications in the ultra-violet light region also make a new promising material in the field of optoelectronics. The throughput of thin GeSe 2 crystal production on compatible substrates, however, has been extremely low, and accordingly, an improvement is essential. Herein, we report the preparation of crystalline GeSe 2 thin films from non-crystalline continuous films of a Ge-Se mixture deposited on a-SiO 2 /Si substrates, and the crystal structure of the post-annealed thin films characterized by X-ray crystallography. Well-oriented crystalline grains with lateral sizes up to 50 μm were observed after an appropriate annealing procedure. This self-aligned growth could establish a facile approach for scaling-up production of oriented crystalline thin films of other Van der Waals layered materials besides GeSe2.