Preparation and optical properties of lamellar GaSe-ZnSe nanocomposites

Abstract

ZnSe-GaSe nanocomposite plates photoluminescent in a photon energy range of 1.80−2.64 eV were obtained via exposing GaSe single-crystal plates to a Zn-vapor heat treatment at temperatures of 673−873 K. The photoluminescence spectrum is dominated by the self-activated emission band of ZnSe with a maximum at 2.04 eV. The average size of the ZnSe crystallites is ~45 nm. The absorption spectrum of the composite consists of two regions characteristic of direct optical transitions in GaSe crystals with a band gap of 1.99 eV and ZnSe crystallites with a band gap of 2.56 eV at room temperature.