Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5491970 | Physica B: Condensed Matter | 2017 | 27 Pages |
Abstract
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.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
A. Arfaoui, M. Mahdouani, R. Bourguiga,