Millimeter Thick, Periodically Oscillating Polarity GaN Grown via HVPE

Gallium Nitride (GaN) crystals have recently garnered attention as a candidate for use as a Quasi-Phase Matching (QPM) material for frequency conversion applications such as second harmonic generation (SHG) and optical parametric oscillation (OPO), due to its wide bandgap (3.4eV), high thermal conductivity (220-260 W/m-k), and wide transparency window (0.36-7um). Additionally, recent work has also demonstrated the ability to produce Periodically Oscillating Polarity GaN (POP-GaN) via several techniques. Such periodically poled structures have been used for QPM in other material systems, such as Lithium Niobate, Potassium Titanyl Phosphate, and GaAs, so the demonstration of periodic poling capability in GaN leads to optimism in utilizing GaN for QPM applications. Growth of large area, thick POP-GaN crystals with an embedded periodic polarity structure present several challenges, which if solved, will provide a commercialization route for POP-GaN as a QPM material with higher performance and wavelength range capability than the existing materials in the market today.