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 x 110 μm and ranging from 200 nm to 2 μm thick. The reaction conditions require tin, tin(IV) iodide, grey 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·s at Vd=-0.9 V and Vg=-60 V.