Nitrogen incorporation in group III–nitride–arsenide materials grown by elemental source molecular beam epitaxy

Abstract

Group III–nitride–arsenides are promising materials for long wavelength opto-electronic devices grown on GaAs substrates. The growth of nitride–arsenides was performed in an elemental solid source molecular beam epitaxy system with a plasma cell to supply reactive nitrogen. Growth is carried out with plasma conditions that maximize the amount of atomic nitrogen versus molecular nitrogen, as determined from the emission spectrum of the plasma. The group III growth rate controls the nitrogen concentration in the film. The photoluminescence intensity of GaNAs and GaInNAs quantum wells (QWs) increases drastically and shifts to shorter wavelengths following high temperature anneal. Nitrogen diffusion out of the QWs is responsible for the wavelength shift. We observe a decrease of interstitial nitrogen after anneal. Vertical-cavity surface-emitting lasers with GaInNAs QWs demonstrated a continuous-wave operation. To limit nitrogen diffusion, the GaAs barriers surrounding the GaInNAs QWs were replaced by GaNAs barriers. This new active region resulted in devices emitting at 1.3 μm.