Preparation and Luminescent Properties of α-ZnSe Heterolayers with Surface Nanostructure

Abstract

A modified surface on -ZnSe heterolayers was prepared by chemical treatment in H2SO4:H2O2 etchant. Visual observation with microscope magnification 150 × and AFM-topograms made it possible to determine the geometrical surface structure which is composed of nanocrystals-pyramids of various size from 20 to 100 nm. Photoluminescence studies revealed high quantum efficiency   15 ÷ 20 % and two radiation spectrum components. In the range of photon energies ħ  Eg (Eg  2.89 eV at 300 K) the wide band with a maximum at ħm  3.24 eV is attributable to quantum size effects. The component at ħm  2.72 eV is formed by radiation on pyramids of large size and determined by interband transitions of free charge carriers and the dominant annihilation of bound excitons. The properties are characterized by temporal and temperature stabilities.

Application of derivative spectroscopy method to photoluminescence in ZnS:Mn nanocrystals

“…An important drawback of the method is its low noise immunity. To overcome the problem, one must use complex and expensive equipment [3].…”