Fig. 1. (Color online) Crystal structures, Brillouin zones, phonon spectra and electrical band structures of (a) puckered and (b) buckled arsenenes. Reproduced with permission^[6], Copyright 2015, American Physical Society. (c) Electrical band structures of buckled arsenene with different layer numbers. Reproduced with permission^[7], Copyright 2015, Wiley-VCH. (d) Schematic illustration for double-gated MOSFET of arsenene. Reproduced with permission^[9], Copyright 2016, Springer Nature.

Fig. 2. (Color online) (a) Cross-sectional image of arsenene grown on InAs substrate. Reproduced with permission^[12], Copyright 2016, American Physical Society. (b) AFM image of black arsenene exfoliated from natural minerals. Reproduced with permission^[13], Copyright 2018, Wiley-VCH. (c) Transfer characteristic of a monolayer black arsenene device. Reproduced with permission^[14], Copyright 2018, Wiley-VCH. (d) Schematic illustration for liquid-phase exfoliation of arsenene from bulk gray arsenic crystals. Reproduced with permission^[15], Copyright 2016, Royal Society of Chemistry. (e) Schematic illustration for growth of gray arsenene nanoflakes on mica. Reproduced with permission^[17], Copyright 2019, American Chemical Society.