High nitrogen incorporation in GaAsN epilayers grown by chemical beam epitaxy using radio-frequency plasma source

Abstract

Nitrogen incorporation in GaAsN epilayers grown by chemical beam epitaxy using a radio-frequency (rf) plasma source as nitrogen precursor was studied as a function of growth conditions. For higher growth temperatures (∼460°C), only higher rf power values yield significant incorporation of nitrogen. The nitrogen incorporation exhibits two behaviors with the growth rate: metal-organic-chemical-vapor-deposition and molecular-beam-epitaxy like behaviors at low and high growth rate, respectively. The highest nitrogen compositions are obtained at rates of about 1 μm/h. Despite a significant reduction of the N incorporation with increasing growth temperature, the optimization of the growth conditions allowed us to reach nitrogen concentrations up to 7.1% for samples fabricated at 460 °C. Films with higher nitrogen content exhibit low-temperature luminescence at energies higher than those predicted using the band-anticrossing model and an extrapolation of the literature data for smaller N composition.