Growth and Dislocation Structure of Single-Crystal Ga (As1−xPx)

Abstract

The preparation of single‐crystal GaAsP by halide vapor transport is described. That dislocation free GaAsP can be achieved was verified experimentally for whiskers grown by the vapor‐liquid‐solid method. In the growth of monocrystalline ingots for device purposes, growth mechanics and the resulting crystal habit are strongly influenced by degenerate Zn, Te, and Se doping. Since n‐type crystals require higher supersaturations, single‐crystal growth is easier to obtain with Zn doping. The as‐grown dislocation structure of ingots with low‐index natural facets is examined by decoration and etching. Typical densities are 5×10³ to 10⁶/cm². From their simple crystallographic orientations different dislocations are identified. 〈211〉, {111} and 〈100〉, {110} edge dislocations are observed in {110} polygonization walls. Values of mobility and carrier density are evaluated from a device point of view. Laser diodes with threshold currents as low as 3000 A/cm² at 33.3% GaP have been obtained from this material.