Semiconductor Physics, Quantum
Electronics & Optoelectronics. 2002. V. 5, N 3. P. 254-257.
PACS: 78.55.Et, 78.67.Hc,
Deep-level defects in CdSe/ZnSe QDs and giant anti-Stokes photoluminescence
CdSe/ZnSe structures with a quantum dot extrinsic photoluminescence band
related to the defects that contain vacancies in cation sublattice has
been investigated. It is shown that such defects can be localized in different
parts of heterostructure (inside ZnSe barrier and cap layers, Zn1-xCdxSe
wetting layer and at quantum dot heterointerface) and their localization
depends on the preparation regimes and parameters of investigated structures.
It is shown that defect level follows the heavy-hole related level. An
intense anti-Stokes photoluminescence of quantum dots has been found.
Two-step excitation mechanism of the anti-Stokes photoluminescence through
the local states of investigated defects localized on the quantum dot
interface is proposed.
dot, deep-level defects, anti-Stokes photoluminescence.