Defects in GaSe grown by Bridgman method.

Optical quality GaSe crystals have been grown by vertical Bridgman method. The structural properties and micromorphology of a cleaved GaSe(001) surface have been evaluated by RHEED, SEM and AFM. The cleaved GaSe(001) is atomically flat with as low roughness as ∼0.06 nm excepting local hillock type defects. The hillock-type formations are round-shaped with a bottom diameter of ∼200 nm and a height of ∼20-35 nm. The drastic depletion of the hillock material by gallium has been indicated by EDX measurements.