Structural and optical properties of InP1-xSbx/n-InAs epilayers grown by gas source molecular beam epitaxy

Experimental photoluminescence (PL), synchrotron resolution extended x-ray absorption fine-structure spectroscopy (SR-EXAFS) and theoretical studies are systematically performed to assess the optical and structural properties of InP1−xSbx/n-InAs epifilms grown by gas-source molecular-beam epitaxy method. For the InP0.63Sb0.37/n-InAs sample, our photoluminescence (PL) study has revealed two A1, A2 bands. The first band, prevalent at low temperature, is attributed to the recombination of carriers trapped in the tail states resulting from compositional disorder. The other band with constant transition energy (0.45 eV – 0.46 eV) is virtually temperature independent. For InP0.63Sb0.37 alloy, the deep level responsible for A2 band is possibly linked to the “vacancy-impurity” like complexes having ground and excited states in the energy gap.