Evidence of isoelectronic traps in molecular beam epitaxy grown Zn1−xBexSe: Temperature- and pressure-dependent photoluminescence studies

We have studied undoped Zn1−xBexSe alloys grown by molecular beam epitaxy by photoluminescence (PL) as a function of temperature and pressure. We suggest that there are isoelectronic excitonic traps in this material. The binding energy of the isoelectronic bound excitons is deep, between 40 and 50 meV. We have also shown that the temperature and pressure dependences of the Zn1−xBexSe PL are close to those of ZnSe. From this we conclude that the dominant excitonic recombination is of an “effective mass” type.