Електронні характеристики квантових точок СdS, що містять дефекти
Using the density functional theory and the generalized gradient approximation, we calculated the atomic structure, the density of electronic states, and the optical absorption spectra of CdS quantum dots containing intrinsic defects — a cadmium vacancy VCd and an interstitial sulfur atom S...
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| Дата: | 2020 |
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| Автори: | , , |
| Формат: | Стаття |
| Мова: | Ukrainian |
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PE "Politekhperiodika", Book and Journal Publishers
2020
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| Онлайн доступ: | https://www.tkea.com.ua/index.php/journal/article/view/TKEA2020.3-4.28 |
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| Назва журналу: | Technology and design in electronic equipment |
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oai:tkea.com.ua:article-1032025-11-08T20:06:25Z Electronic characteristics of CdS quantum dots with defects Електронні характеристики квантових точок СdS, що містять дефекти Kupchak, Ihor Korbutyak, Dmytro Serpak, Natalya quantum dots defects vacancy CdS density functional method квантові точки дефекти вакансія CdS метод функціоналу густини Using the density functional theory and the generalized gradient approximation, we calculated the atomic structure, the density of electronic states, and the optical absorption spectra of CdS quantum dots containing intrinsic defects — a cadmium vacancy VCd and an interstitial sulfur atom SI, and substitutional impurities — zinc and copper in place of the atom cadmium — ZnCd and CuCd, respectively. The calculations were performed for the Cd33S33 cluster corresponding to the so-called "magic" size of the quantum dot. This size has a minimum of dangling bonds at the surface and allows the using of such a cluster without the passivation. The structural relaxation during the formation of such defects and the distribution of the wave function of the state corresponding to the top of the valence band are analyzed in details. It has been shown that the cadmium vacancy forms local states in the band gap of CdS nanocrystals, and can serve as centers of radiative recombination. Other defects form energy levels in the depths of the valence band or near its top, but whose energy positions do not correspond to the band maxima in the experimental photoluminescence spectra of CdS quantum dots, both undoped and doped with zinc. The calculated optical absorption spectra demonstrate a strong peak in the region of fundamental absorption of CdS for a cluster containing a substitutional impurity of CuCd, in contrast to other systems where no such peaks are observed. In addition, the replacement of the cadmium atom with copper leads to a decrease in the number of chemical bonds to three and, accordingly, to the largest relaxation among the systems studied. This feature is caused by the crystal structure inhomogeneity of copper sulfide CuxS, which, depending on stoichiometry, can be either a semiconductor or a metal. Методом функціоналу густини з використанням базису плоских хвиль розраховано атомну структуру, густину електронних станів та спектри поглинання квантових точок CdS, що містять власні дефекти та домішки заміщення. Показано, що локальні стани у забороненій зоні таких нанокристалів формуються вакансіями кадмію і можуть бути центрами випромінювальної рекомбінації, тоді як інші утворюють енергетичні рівні або у глибині валентної зони, або поблизу її вершини. PE "Politekhperiodika", Book and Journal Publishers 2020-08-27 Article Article Peer-reviewed Article application/pdf https://www.tkea.com.ua/index.php/journal/article/view/TKEA2020.3-4.28 10.15222/TKEA2020.3-4.28 Technology and design in electronic equipment; No. 3–4 (2020): Tekhnologiya i konstruirovanie v elektronnoi apparature; 28-34 Технологія та конструювання в електронній апаратурі; № 3–4 (2020): Технология и конструирование в электронной аппаратуре; 28-34 3083-6549 3083-6530 10.15222/TKEA2020.3-4 uk https://www.tkea.com.ua/index.php/journal/article/view/TKEA2020.3-4.28/93 Copyright (c) 2020 Kupchak I. M., Korbutyak D. V., Serpak N. F. http://creativecommons.org/licenses/by/4.0/ |
| institution |
Technology and design in electronic equipment |
| baseUrl_str |
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| datestamp_date |
2025-11-08T20:06:25Z |
| collection |
OJS |
| language |
Ukrainian |
| topic |
квантові точки дефекти вакансія CdS метод функціоналу густини |
| spellingShingle |
квантові точки дефекти вакансія CdS метод функціоналу густини Kupchak, Ihor Korbutyak, Dmytro Serpak, Natalya Електронні характеристики квантових точок СdS, що містять дефекти |
| topic_facet |
quantum dots defects vacancy CdS density functional method квантові точки дефекти вакансія CdS метод функціоналу густини |
| format |
Article |
| author |
Kupchak, Ihor Korbutyak, Dmytro Serpak, Natalya |
| author_facet |
Kupchak, Ihor Korbutyak, Dmytro Serpak, Natalya |
| author_sort |
Kupchak, Ihor |
| title |
Електронні характеристики квантових точок СdS, що містять дефекти |
| title_short |
Електронні характеристики квантових точок СdS, що містять дефекти |
| title_full |
Електронні характеристики квантових точок СdS, що містять дефекти |
| title_fullStr |
Електронні характеристики квантових точок СdS, що містять дефекти |
| title_full_unstemmed |
Електронні характеристики квантових точок СdS, що містять дефекти |
| title_sort |
електронні характеристики квантових точок сds, що містять дефекти |
| title_alt |
Electronic characteristics of CdS quantum dots with defects |
| description |
Using the density functional theory and the generalized gradient approximation, we calculated the atomic structure, the density of electronic states, and the optical absorption spectra of CdS quantum dots containing intrinsic defects — a cadmium vacancy VCd and an interstitial sulfur atom SI, and substitutional impurities — zinc and copper in place of the atom cadmium — ZnCd and CuCd, respectively. The calculations were performed for the Cd33S33 cluster corresponding to the so-called "magic" size of the quantum dot. This size has a minimum of dangling bonds at the surface and allows the using of such a cluster without the passivation. The structural relaxation during the formation of such defects and the distribution of the wave function of the state corresponding to the top of the valence band are analyzed in details. It has been shown that the cadmium vacancy forms local states in the band gap of CdS nanocrystals, and can serve as centers of radiative recombination. Other defects form energy levels in the depths of the valence band or near its top, but whose energy positions do not correspond to the band maxima in the experimental photoluminescence spectra of CdS quantum dots, both undoped and doped with zinc. The calculated optical absorption spectra demonstrate a strong peak in the region of fundamental absorption of CdS for a cluster containing a substitutional impurity of CuCd, in contrast to other systems where no such peaks are observed. In addition, the replacement of the cadmium atom with copper leads to a decrease in the number of chemical bonds to three and, accordingly, to the largest relaxation among the systems studied. This feature is caused by the crystal structure inhomogeneity of copper sulfide CuxS, which, depending on stoichiometry, can be either a semiconductor or a metal. |
| publisher |
PE "Politekhperiodika", Book and Journal Publishers |
| publishDate |
2020 |
| url |
https://www.tkea.com.ua/index.php/journal/article/view/TKEA2020.3-4.28 |
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2025-09-24T17:30:13Z |
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2025-11-09T02:38:26Z |
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