Preparation of Black Phosphorus Single Crystals by a Completely Closed Bismuth-Flux Method and Their Crystal Morphology

Abstract

Needle-shaped and film- or plate-shaped black phosphorus single crystals were prepared by an improved bismuth-flux method. The conversion of red phosphorus to white phosphorus and the growth of black phosphorus single crystals from the solution of white phosphorus in liquid bismuth were performed in an evacuated quartz-glass apparatus without breaking the vacuum. Needle crystals measured about 5 mm in length and 10 to 100 µm in thickness. The thickness of film or plate crystals ranged from 1 to 10 µm and the width was usually above 100 µm, generally increasing with decreasing thickness. Some crystal morphologies were observed and analyzed crystallographically.