Meniscus lines as nucleation sites for the active layer of a double-heterostructure laser grown by LPE

Abstract

It is demonstrated that at relatively low supersaturation the active layer of a DH laser nucleates on the meniscus lines on a surface which is not strongly terraced. It is further demonstrated that there is a finite angle of contact between the nucleating solid and the lower layer which results in the active layer growing as islands about each nucleation site. As a result, there is a minimum thickness of the active layer which is continuous. These observations are a possible explanation for the phenomenon which has been described as "rake lines" in DH laser structures and explains in general the difficulties encountered in trying to fabricate lasers with very thin active layers.