II-VI semiconductors are very attractive materials for construction of laser diodes (LDs), light emitting diodes (LEDs) and photodetectors operating in the UV and visible spectral range.1,2 The ZnCdMgSe-based compounds have also been proposed as an alternative material system for intersubband (ISB) devices such as quantum cascade lasers3 and quantum well infrared (IR) photodetectors,4 as well as ultrafast all-optical switches 5 of mid- and near-IR region. The present work describes a detailed study of near band-edge transitions of Zn1-x-yBexMgySe solid solutions grown by the modified high pressure Bridgman method, using temperature-dependent photoluminescence (PL), contactless electroreflectance (CER) and photoreflectance (PR) measurements. The effect of Mg/Zn content ratio on properties of Zn1-x-yBexMgySe is discussed.figureFig. 1. (a) low temperature PL typical for Cd1-x-yZnxMgySe with varying content of Zn and Mg.; (b) PR, CER and PL spectra near the band-edge at 300 KAt low temperature (Fig. 1(a)), the PL spectra of Zn1-x-yBexMgySe mixed crystals consist of an excitonic sharp peak X followed by a broad edge-emission feature corresponding to radiative recombination of shallow donor-acceptor pairs (DAP) and a broad deep levels (DL) bands.Displayed by the dotted lines in Fig. 1(b), the experimental PR and CER spectra of Cd1-x-yZnxMgySe at 300 K show three distinct exciton resonances, denoted as E A 0 , EB 0 and EC0 that is typical for wurtzite-type crystal structure. The near bandedge excitonic transition energies determined from CER correspond quite well to those obtained from PR and slightly higher than the peak positions of the band-edge excitonic features in the PL spectra (Fig. 1(b)).