From GaAs:N to oversaturated GaAsN: Analysis of the band-gap reduction

摘要: The composition dependence of the band-gap reduction ${\mathrm{GaAs}}_{1\ensuremath{-}x}{\mathrm{N}}_{x}$ grown by molecular beam epitaxy and metal organic vapor phase was investigated using transmission, reflection, low-temperature photoluminescence (PL) spectroscopy for N incorporations ranging from doping concentrations up to $x=5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}.$ We identified four different regimes incorporation with distinctly scaling. N-doped GaAs shows sharp PL lines due cluster states, but no significant change in band gap. In ultradilute region ${(10}^{\ensuremath{-}5}\ensuremath{\lesssim}xl~1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3})$ a strong observed which scales according x, irrespective local distribution atoms As sublattice. same scaling InGaAsN after corrections strain alloying. an intermediate compositional $(1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}l~xl~2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2})$ $\ensuremath{\Delta}{E}_{g}$ ${x}^{2/3}.$ At higher $(xg2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2})$ weakens effects connected oversaturation