Low pressure–temperature–gas flow HVPE growth of GaP for nonlinear optical frequency conversion devices

This paper describes advances in the development of quasi-phase-matched (QPM) gallium phosphide (GaP) crystals for agile laser sources in the mid-infrared regions between 3–5 and 8–12 μm. In the quest for a nonlinear optical material with the potential to efficiently convert near infrared energy (wavelength ∼1 μm) to a powerful mid-infrared source, we have investigated the growth of GaP by hydride vapor phase epitaxy (HVPE). The process is shown to produce high quality thick layers at rapid growth rates in a low-pressure horizontal reactor. This process was used to grow thick layers on orientation-patterned (OP) templates. The OP-GaP templates were fabricated by lithographic patterning of inverted wafer-fused GaP. HVPE growth on both OP-GaP and OP-GaAs templates was performed, showing that HVPE can successfully replicate the initial template pattern. However, for longer growth duration at given conditions the patterned structure can be lost, with annihilation of every other domain.