Optical and structural properties of Zn1-xBexSe mixed crystals

Optical and structural properties of Zn1 - xBexSe bulk crystals in the range of composition 0 less than or equal to x less than or equal to 0.41 have been studied. These crystals were grown by Bridgman method under an argon overpressure. Transmission, absorption, photoluminescence and photoacoustic spectra as a function of composition were investigated. It has been found that the crystal structure is of sphalerite type. The crystal quality increases when the crystallization process of the same boule is performed more than once. In the investigated composition range the lattice constant decreases and the energy gap increases with increasing beryllium content. From photoluminescence measurements the excitonic energy gap about 3.64 eV at 40 K was estimated for the highest obtained Be concentration (x = 0.41).