Optical properties study of In_xGa_(1-x)As/GaAs structures using spectral reflectance, photoreflectance and near-infrared photoluminescence

摘要

Optical properties of In_xGa_(1-x)As films grown on GaAs substrates by metalorganic vapor phase epitaxy were investigated. Spectral reflectance (SR) and photoreflectance (PR) at room temperature and near-infrared photoluminescence (PL) at 10 K were performed. SR signals in the range of 200-1700 nm provided the x-dependence of the critical point energies E_1, E_1+ Δ_1 and E_2. Furthermore, band-gap and spin-orbit splitting energies, as well as their broadening parameters were determined from PR spectra and studied as function of In composition ranging from 0 to 0.37. On the other hand, the origins of luminescence bands observed in PL spectra were revealed. A redshift of 16 meV/%In in the band-to-band transition was obtained. All results issued from different characterizations tools are correlated and compared to the literature.