CdSe/ZnCdSe Quantum Dot Heterostructures for Yellow Spectral Range Grown on GaAs Substrates by Molecular Beam Epitaxy
| Autor: | G. V. Klimko, I. V. Sedova, Sergei Gronin, S. V. Sorokin, E. A. Evropeytsev, Sergei Ivanov, D.R. Kazanov |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Acta Physica Polonica A. 126:1096-1099 |
| ISSN: | 1898-794X 0587-4246 |
| DOI: | 10.12693/aphyspola.126.1096 |
| Popis: | This paper reports on theoretical calculations and fabrication by molecular beam epitaxy of wide-gap II VI heterostructures emitting in the true yellow range (560 600 nm) at room temperature. The active region of the structures comprises CdSe quantum dot active layer embedded into a strained Zn1−xCdxSe (x = 0.2−0.5) quantum well surrounded by a Zn(S,Se)/ZnSe superlattice. Calculations of the CdSe/(Zn,Cd)Se/Zn(S,Se) quantum dot quantum well luminescence wavelength performed using the envelope-function approximation predict rather narrow range of the total Zn1−xCdxSe quantum well thicknesses (d ≈ 2−4 nm) reducing e ciently the emission wavelength, while the variation of x (0.2 0.5) has much stronger e ect. The calculations are in a reasonable agreement with the experimental data obtained on a series of test heterostructures. The maximum experimentally achieved emission wavelength at 300 K is as high as 600 nm, while the intense room temperature photoluminescence has been observed up to λ = 590 nm only. To keep the structure pseudomorphic to GaAs as a whole the tensile-strained surrounding ZnS0.17Se0.83/ZnSe superlattice were introduced to compensate the compressive stress induced by the Zn1−xCdxSe quantum well. The graded-index waveguide laser heterostructure with a CdSe/Zn0.65Cd0.35Se/Zn(S,Se) quantum dot quantum well active region emitting at λ = 576 nm (T = 300 K) with the 77 to 300 K intensity ratio of 2.5 has been demonstrated. |
| Databáze: | OpenAIRE |
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