کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5491970 | 1525131 | 2017 | 27 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Investigation of the exciton emission lifetime in type-II spherical core/shell semiconductor heteronanostructures
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موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
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چکیده انگلیسی
The two-band model effective mass approximation has been adopted to explain the energy spectra in type-I CdSe core-only and type-II CdSe/CdTe core/shell quantum dots (QDs). As optical properties, the emission wavelength, the electron-hole overlap integral and the radiative recombination lifetime have been investigated. The simulated emission spectra are in good agreement with available experimental results for both core-only and core/shell QDs. The radiative recombination lifetime (Ïrad) has been investigated in different carrier localization regimes and compared to that corresponding to core-only QDs. We have found a sudden increase in Ïrad at around r1~1.1nm suggesting the transition of the heterostructure from the quasi-type-II to the type-II regime. A monotonic increase in Ïrad with the core and shell sizes (geometric parameters) was observed. Also found is the possibility of increasing Ïrad over two orders of magnitude with a suitable change in the geometric parameters. The long radiative lifetime produced by increasing the geometric parameters is found due to spatial separation of the carriers, which makes the type-II core/shell QDs made from large core and shell sizes promising for photovoltaic applications.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physica B: Condensed Matter - Volume 518, 1 August 2017, Pages 68-76
Journal: Physica B: Condensed Matter - Volume 518, 1 August 2017, Pages 68-76
نویسندگان
A. Arfaoui, M. Mahdouani, R. Bourguiga,