Single-crystal growth from the vapour and etch pit studies in arsenic

Abstract

Strain-free single crystals of the rhombohedral (α) semimetallic form of arsenic have been grown from the vapour. Large crystals can only be grown when the deposition temperature is above a critical value of about 700°C. Temperature fluctuations must be kept within 0·2 degc to prevent development of a severe mosaic structure. Dislocations have been examined by etching techniques. Either trigonal or hexagonal pits may be produced at the same site of emergence of dislocations on the (111) cleavage planes; the etch determines the pit shape.