Photoluminescence studies on the layer semiconductor In2Se3

Photoluminescence investigations of the layered In2Se2 show clearly distinct results for two varieties of materials : pure σ-In2Se3 and mixture of α and λ-In2Se3. The pure α-In2Se3 exhibits, at liquid helium temperature, two photoluminescence bands : one at higher energy 1.523 eV due to the radiative recombination of impurity bound excitons, and the other at lower energy 1,326 eV due to recombination on luminescence centers formed by intrinsic defects due to disorder in the cation sublattice. In the mixed α- and λ-In2Se3 only one broad band at 1.319 eV is observed related to the additional disorder in the cation sublattice coming from the alloying of the α- and λ-phases.