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

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

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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 »« less

Authors:: Gong, Y; MacDonald, W; Neumark, G; Tamargo, M; Kuskovsky, I

Publication Date:: 2008-01-01

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

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                    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. 
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                    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.

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                    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.

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@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}

}

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