Bimetallic Alloys b-As x P 1- x at High Concentration Differences: Ideal for Photonic Devices.

Black arsenic phosphorus (b-As x P 1- x ) is expected to be one of the primary materials for future photonic devices. However, the x -factor is randomly estimated and applied in photonic devices in current studies, rather than systematically analyzing it for a comprehensive understanding. Herein, As x P 1- x switches from a direct band gap semiconductor to an indirect band gap one at x = 0.75. As x P 1- x at x ≤ 0.25 is capable of broadband absorption, while b-As x P 1- x at x ≥ 0.75 can only absorb at specific wavelengths in the perspective of the electron energy transition. Additionally, the optoelectronic response of the integral field-effect transistor configurations constructed with b-As x P 1- x is investigated systematically as a photodetector device. The photonic response characteristics show high polarization sensitivity at x ≥ 0.75, but a typical circuit system signal at x ≤ 0.25. These results suggest that b-As x P 1- x with high concentration differences is a perfect candidate for photonic material.