ZnSe based films characterization by cathodoluminescence

Abstract

Abstract In this work the cathodoluminescence investigation have been used to study the ZnSe based films. ZnSe, ZnS y Se 1– y and Zn 1− x Mg x S y Se 1− y films were grown by molecular beam epitaxy with different composition measured by electron probe microanalysis. The film band gap structure and defect energy levels were determined by cathodoluminescence intensity measurements. The cathodoluminescence intensity time variation was measured in dependence on electron beam current density and sample temperature for free exciton recombination band at stationary electron beam irradiation. The cathodoluminescence intensity time variation for different samples points to electron traps with different activation energies that are present depending on sample quality. The presence of deep acceptor levels has been established, with activation energies of around 0.02–0.05 eV. The defect levels are probably associated with a lattice defect like Se vacancy or defect complexes.