Origin and evolution of threading dislocation in CdZnTe(001)/GaAs(001) epilayer grown by close spaced sublimation

摘要

The origin and evolution of threading dislocations (TDs) in CdZnTe(0 0 1)/GaAs(0 0 1) epilayer grown by close spaced sublimation (CSS) were experimentally investigated. The dislocation formed at the initial growth stage was observed and analyzed by the plan-view (scanning) transmission electron microscopy (STEM). The thickness-dependent migration and recombination of TDs along the growth direction were revealed by the dislocation etch pit. The origin of TDs is mainly related to the mismatch of growth domains. Strong lateral migration of dislocation in film can be explained by epitaxial lateral overgrowth (ELO) process. The blocking effect on TD movement by growth pit which is related to antiphase boundary (APB) is the primary cause of epilayer quality deterioration.