Study of the multiband exciton spectrum of ZnSe in the range of 477-490 nm

Abstract

The photoluminescence spectra of CVD (chemical vapour deposition) ZnSe polycrystalline grown with a large excess of selenium and containing \O*Se-Cu+i\ complexes at stacking faults are studied. Absorbance was measured to complement these data. The features of the PL spectra in comparison with cathodoluminescence are considered. It is shown that PL bands identical to CL are observed as somewhat shorter wavelengths. For the studied crystals, a band model is presented according to the data obtained in this work. The low-energy shift of the PL spectra with decreasing excitation energy corresponds to a shift on the energy scale of the band model with a corresponding change in the type of radiative transitions. It is shown that identical photoluminescence bands are observed as somewhat shorter wavelengths than cathodoluminescence bands. For the crystals under study, a band model is presented according to the data obtained in the given decreasing work. The low-energy shift of the photoluminescence spectra upon the excitation energy corresponds to a shift along the energy scale of the band model with a corresponding change in the type of radiative transitions. Changes have been introduced that characterize the nature of the group of equidistant bands 477-490 nm, which are characteristic of ZnSe samples with an excess of oxygen and Se. The results can be useful for a more complete study of the structure of multiphonon exciton spectra of photo and cathodoluminescence of AIIBVI crystals. Keywords: band model, narrow-line multi-photon spectra, exciton radiation, stacking faults, isoelectronic oxygen impurity, carrying effective negative charge.

Main effects of oxygen centers in A-=SUP=-II-=/SUP=-B-=SUP=-VI-=/SUP=- optics

“…According to [3][4][5][6], the spectral shift of these narrow lines is absent with increasing temperature. A study of the 477 nm band in pulsed CL spectra [3,7] showed that its maximum does not shift with increasing excitation intensity, when the band dominates in the spectra.…”

“…Refinement of the position of the E SF + level in the ZnSeSe(O) band model according to the data of [6] made it possible to determine the nature of the narrow bands. In fig.…”

“…Our investigations of the edge luminescence of CdS, ZnS and ZnSe also revealed a group of narrow bands due to bound excitons (BE ex ) at oxygen centers in layers of stacking faults (SF) [1][2][3][4][5][6][7].…”