Order–disorder transition in epitaxial ZnSnP2

We report on the growth of ${\mathrm{ZnSnP}}_{\mathrm{2}}$ on GaAs(100) substrates by gas source molecular beam epitaxy. Samples were grown in the temperature range of 300–360 °C. A small change in the Sn/Zn flux ratio at constant substrate temperature was found to result in a transition from a lattice mismatched, $\text{Δa/a∼0.4\%–0.7\%,}$ disordered crystal structure to a lattice matched, ordered chalcopyrite structure. Infrared reflectance and Raman measurements were used to monitor this phase transition. Formation of the two different crystal modifications is discussed in terms of vapor–solid and vapor–liquid–solid growth modes.