Fig. 1. (Color online) (a) b-As_xP_1−x crystal. (b) The band structure of multilayer b-AsP. (c) Enlarged image of the energy band in (b), in which the band has been split into four sub-bands. Reproduced with permission^[17], Copyright 2018, IOP Publishing. (d) b-As_0.83P_0.17 crystal synthesized by CVT. Reproduced with permission^[7], Copyright 2015, WILEY-VCH. (e) AFM image for an exfoliated bilayer b-As_0.83P_0.17 flake. (f) Height profile for the exfoliated bilayer b-As_0.83P_0.17 flake with a thickness of ~1.3 nm. Reproduced with permission^[8], Copyright 2019, Optical Society of America.

Fig. 2. (Color online) (a) The preparation of 2D b-AsP nanosheets by the liquid-phase exfoliation method. Reproduced with permission^[11], Copyright 2020, American Chemical Society. (b) The MBD synthesis of b-AsP alloys. Reproduced with permission^[12], Copyright 2018, American Chemical Society. (c) The hBN/b-As_0.83P_0.17/hBN heterostructure photodetector. (d) The cross-section of the device by TEM is shown on the left. The elemental mapping is shown on the right. Reproduced with permission^[13], Copyright 2018, American Chemical Society.