Composition dependence of the positron annihilation in Zn1-xBexSe

In order to clarify the electronic and optical properties of wide-energy gap zinc-blende structure ZnSe, BeSe and their alloys, a simple pseudo-potential scheme (EPM), within an affective potential the virtual crystal approximation (VCA) which incorporates compositional disorder as an effective potential are presented. Angular correlation of positron annihilation radiation (ACPAR) along different crystallographic directions in Zn1-xBexSe are calculated. We observe that the electron-positron momentum density increases rapidly with increasing Beryllium content.