The Growth of, and the Formation of Grain Boundaries in, Cu2 S Films Grown on Faceted Single Crystal CdS Substrates

Abstract

It is shown that large angle grain boundaries are formed in the film at the intersection of adjacent prismatic planes and that small angle grain boundaries are formed at the intersection of adjacent prismatic and non‐prismatic planes and at the intersection of a nonprismatic plane with the basal plane. The large angle grains are formed because the orthorhombic c‐axis is at most a 2‐fold axis whereas the axis is a 6‐fold axis. It is shown that the open‐circuit voltage is reduced in the vicinity of these grain boundaries. The small angle grain boundaries form because the effective c/a axis of is different than the c/a axis of so that the is distorted when it is made to conform with the substrate. The open‐circuit voltage in the vicinity of these grain boundaries did not noticeably decrease. It is also shown that the growth rate and morphology of the films depend on the orientation and morphology of the substrate.