Band structure and optical properties of In y Ga 1 − y As 1 − x N x alloys

摘要: We have carried out comprehensive studies of the nitrogen-induced modifications electronic structure ${\mathrm{In}}_{y}{\mathrm{Ga}}_{1\ensuremath{-}y}{\mathrm{As}}_{1\ensuremath{-}x}{\mathrm{N}}_{x}$ alloys. Temperature- and composition-dependent optical absorption spectra been measured on free-standing layers thin films lattice matched to GaAs with $0l~x=3yl~0.025$ in photon energy range 0.8--2.5 eV. The measurements provided information transitions at \ensuremath{\Gamma} point Brillouin zone. Spectroscopic ellipsometry performed a wide 1.5--5.5 eV used determine dependence dielectric function as well energies ${E}_{1},$ ${E}_{0}^{\ensuremath{'}},$ ${E}_{2}$ critical transitions. Measurements plasma edge frequency for samples different electron concentrations dispersion relation lowest conduction band. results show large effect nitrogen relations band states close point. They can be consistently explained terms recently proposed anticrossing model. On other hand, observed small N transition high-energy points understood within virtual crystal approximation. insensitivity content is disagreement theoretical calculations predicting incorporation X L minima.