Effect of growth temperature on nitrogen incorporation into GaAsN during liquid-phase epitaxy

Abstract

We studied the growth temperature effect on nitrogen incorporation into GaAsN layers grown by liquid-phase epitaxy (LPE). The growth of dilute nitrides at nearly equilibrium conditions during LPE presents several major challenges: low solubility of nitrogen in Ga-melt, small incorporation efficiency in the solid and high volatility of nitrogen. GaAsN layers are grown from three different initial epitaxy temperatures: 580 °C, 680 °C and 780° C using GaN powder in the melt as a source of nitrogen. The N content in GaAsN is estimated from X-ray diffraction curves applying Vegard’s law. The local microstructure and surface morphology of the grown layers are studied by Fourier-transform infrared spectroscopy and atomic force microscopy measurements, respectively. The absorption edge and the composition dependence of the effective band gap are determined by employing optical transmission and surface photovoltage spectroscopies.