Open AccessSpectroscopic evidence of tunnel coupling between CdTe quantum wells in the CdTe/ZnTe heterostructures
Author(s) -
V. F. Agekyan,
N. G. Filosofov,
G. Karczewski,
A. Yu. Serov,
I. V. Shtrom,
A. Reznitsky
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/2103/1/012102
Subject(s) - quantum well , photoluminescence , excited state , cadmium telluride photovoltaics , heterojunction , wavelength , excitation , quantum tunnelling , relaxation (psychology) , monolayer , materials science , chemistry , optoelectronics , molecular physics , atomic physics , laser , optics , physics , nanotechnology , psychology , social psychology , quantum mechanics
The photoluminescence (PL) spectra of CdTe/ZnTe double quantum wells (QWs) are studied on a series of samples containing two CdTe layers with nominal thicknesses of 2 and 4 monolayers (ML) in the ZnTe matrix. The QWs were grown in atomic-layer epitaxy and separated by ZnTe spacers with the thicknesses d sp =40−160 ML. The dependences of the relative intensity of shallow QW 1 and deep QW 2 PL bands ( I 1 and I 2 , respectively) on the pump intensity (J) when excited by the lasers with different radiation wavelengths are investigated. It is found that in the sample with d sp =40 ML, the ratio Y(J)=I 1 /I 2 depends on J and the shape of the Y ( J ) dependency changes with the excitation wavelength. In the samples with d sp > 70 ML Y ( J ) also changes with the excitation intensity J, but the shape of this dependence is the same for various excitation wavelengths. It is concluded that the energy relaxation in these samples is influenced not only by the tunneling of charge carriers from QW 1 to QW2, but also by carrier relaxation at the nonradiative centers, for which the recombination rate is different for shallow and deep QWs.