Growth of black arsenic phosphorus thin films and its application for field-effect transistors

Black arsenic phosphorus single crystals were grown using a short-way transport technique resulting in crystals up to 12 110 μm and ranging from 200 nm to 2 μ m thick. The reaction conditions require tin, tin (IV) iodide, gray arsenic, and red phosphorus placed in an evacuated quartz ampule and ramped up to a maximum temperature of 630 C. The crystal structure and elemental composition were characterized using Raman spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy, cross-sectional transmission microscopy, and electron backscatter diffraction. The data provides valuable insight into the growth mechanism. A previously developed b-P thin film growth technique can be adapted to b-AsP film growth with slight modifications to the reaction duration and reactant mass ratios. Devices fabricated from exfoliated bulk-b-AsP grown in the same reaction condition as the thin film growth process are characterized, showing an on-off current ratio of 102, a threshold voltage of -60 V, and a peak field-effect hole mobility of 23 cm2 V-1 s-1 at V d = -0.9 V and V g = -60 V.