Controllable preparation and photoelectric properties of oriented two-dimensional GeSe2 nanobelt arrays

Abstract

Germanium diselenide (GeSe2) nanobelts are synthesized by atmospheric-pressure chemical vapor deposition under low temperature by using Se and Ge powders as precursor materials in a quartz tube furnace with double heating zones. The GeSe2 nanobelts thus prepared exhibit growth directionality. Unidirectional nanobelt clusters are tightly spaced and shaped as rectangular nanobelt arrays. Additionally, the thickness of the prepared GeSe2 material is less than 5 nm, and the area of a single array can attain 0.96 mm2. Our experimental results show that hydrogen directly affects the growth of GeSe2. First-principles calculations reveal the electronic properties and in-plane anisotropic optical absorption of the few-layer two-dimensional GeSe2 material. Optical absorbance measurements of GeSe2 nanobelt arrays reveal high ultraviolet absorbance of GeSe2 (200–400 nm). Photodetectors based on GeSe2 nanobelts are p-type, with high responsivity, superior detectivity, and a fast response time. These results show that GeSe2 is an excellent ultraviolet photoelectric material with potential photoelectronic applications.