ZnGeP2 grown by the liquid encapsulated Czochralski method

Abstract

The growth of ZnGeP2 by the liquid encapsulated Czochralski method is reported for the first time herein. Large boules of ZnGeP2, with diameters up to 40 mm and weights up to 400 gm were grown by Czochralski pulling from B2O3 encapsulated melts under high pressure (20 atm Ar) using axial gradients ≤120 °C/cm. Boules pulled at ≤4 mm/h exhibited large (50×20×15 mm3) monocrystalline grains of α-phase ZnGeP2 with room temperature electrical properties of p-type conduction, carrier concentrations ranging from 1012 to 1016 cm−3, and mobilities of 20 cm2/V s or less. Optical samples exhibited broad IR transmission (0.7 to 12.5 μm), second harmonic generation at 4.7 μm with 7.2% conversion efficiency, a broad subband gap photoluminescence signature, and near band-edge absorption similar to that observed in Bridgman-grown ZnGeP2.