Optical properties of Zn0.5Cd0.5Se thin films grown on InP by molecular beam epitaxy

We report photoluminescence (PL) and reflectivity measurements of Zn0.5Cd0.5Se epilayers grown by molecular beam epitaxy on InP substrates. The low-temperature PL spectra are dominated by asymmetric lines, which can be deconvoluted into two Gaussian peaks with a separation of ∼8 meV. The behavior of these peaks is studied as a function of excitation intensity and temperature, revealing that these are free exciton (FE) and bound exciton emission lines. Two lower energy emission lines are also observed and assigned to the first and second longitudinal optical phonon replicas of the FE emission. The temperature dependence of the intensity, line width, and energy of the dominant emission lines are described by an Arrhenius plot, a Bose–Einstein type relationship, Varshniʹs and Bose–Einstein equations, respectively.