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Title: Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration-Enhanced Epitaxy

Abstract

The properties of multiple type-II ZnTe/ZnSe quantum dots (QDs), which are coexistent with isoelectronic centers formed by Te, grown by migration-enhanced epitaxy, are studied. The samples with a single deposition cycle of Zn-Te-Zn sandwiched between ZnSe barriers are investigated via temperature- and excitation-dependent photoluminescence (PL) as well as magneto-PL measurements. It is found that the PL consists of two broad bands: a 'blue' band, which is dominant at low temperatures, and a 'green' band, which is observed at T=60 K. Upon increasing the excitation intensity by about 4 orders of magnitude, the peak energy position of the blue band remains nearly the same, whereas the green band exhibits a large blueshift of {approx}50 meV, which suggests that the green band is due to, at least partially, the recombination of excitons bound to type-II QDs. The existence of type-II ZnTe/ZnSe QDs is further supported by the results of magneto-PL, for which the oscillation in the PL intensity as a function of magnetic field is observed. The properties of ZnTe/ZnSe QDs grown under the same Zn/Te flux ratio but with one and three contiguous deposition cycles of Zn-Te-Zn are compared. It is concluded that type-II QDs are formed in both types ofmore » samples; however, the density, size, and chemical composition of QDs strongly depend on the deposition of the submonolayer quantities of ZnTe.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
960015
Report Number(s):
BNL-83001-2009-JA
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US1005872
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Physical Review B: Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 77; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHEMICAL COMPOSITION; DEPOSITION; EPITAXY; EXCITATION; EXCITONS; MAGNETIC FIELDS; OPTICAL PROPERTIES; OSCILLATIONS; PHOTOLUMINESCENCE; QUANTUM DOTS; RECOMBINATION; national synchrotron light source

Citation Formats

Gong, Y, MacDonald, W, Neumark, G, Tamargo, M, and Kuskovsky, I. Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration-Enhanced Epitaxy. United States: N. p., 2008. Web.
Gong, Y, MacDonald, W, Neumark, G, Tamargo, M, & Kuskovsky, I. Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration-Enhanced Epitaxy. United States.
Gong, Y, MacDonald, W, Neumark, G, Tamargo, M, and Kuskovsky, I. Tue . "Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration-Enhanced Epitaxy". United States.
@article{osti_960015,
title = {Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration-Enhanced Epitaxy},
author = {Gong, Y and MacDonald, W and Neumark, G and Tamargo, M and Kuskovsky, I},
abstractNote = {The properties of multiple type-II ZnTe/ZnSe quantum dots (QDs), which are coexistent with isoelectronic centers formed by Te, grown by migration-enhanced epitaxy, are studied. The samples with a single deposition cycle of Zn-Te-Zn sandwiched between ZnSe barriers are investigated via temperature- and excitation-dependent photoluminescence (PL) as well as magneto-PL measurements. It is found that the PL consists of two broad bands: a 'blue' band, which is dominant at low temperatures, and a 'green' band, which is observed at T=60 K. Upon increasing the excitation intensity by about 4 orders of magnitude, the peak energy position of the blue band remains nearly the same, whereas the green band exhibits a large blueshift of {approx}50 meV, which suggests that the green band is due to, at least partially, the recombination of excitons bound to type-II QDs. The existence of type-II ZnTe/ZnSe QDs is further supported by the results of magneto-PL, for which the oscillation in the PL intensity as a function of magnetic field is observed. The properties of ZnTe/ZnSe QDs grown under the same Zn/Te flux ratio but with one and three contiguous deposition cycles of Zn-Te-Zn are compared. It is concluded that type-II QDs are formed in both types of samples; however, the density, size, and chemical composition of QDs strongly depend on the deposition of the submonolayer quantities of ZnTe.},
doi = {},
url = {https://www.osti.gov/biblio/960015}, journal = {Physical Review B: Condensed Matter and Materials Physics},
issn = {0163-1829},
number = ,
volume = 77,
place = {United States},
year = {2008},
month = {1}
}