期刊
NANOTECHNOLOGY
卷 24, 期 20, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0957-4484/24/20/205701
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资金
- Generalitat Valenciana Grants [PROMETEO/2009/074, ISIC/2012/008]
- Spanish MINECO [TEC2011-29120-C05-01]
- Nano PV [FP7 NMP-246331]
- JAE-Predoc grant
A study based on photoluminescence and absorption measurements as a function of temperature and pressure for PbSe nanocrystals with sizes in the range 3-13 nm reveals the influence of size quantum confinement on the observed variation. In the case of the temperature variation, the effective bandgap changes from showing a positive rate of change to showing a negative one (for a quantum dot 3 nm in diameter), which can be accounted for by incorporating a linear variation of the carrier effective masses into a simple calculation of the exciton ground state in the quantum dot. In the case of the pressure variation, we observe a clear inverse correlation between the absolute value of the pressure coefficient and the nanocrystal size, a signature of quantum size confinement, with values changing from -76 to -41 meV GPa(-1) for quantum dots ranging from 13 to 3 nm in diameter, respectively, clearly smaller in absolute value than the rate for bulk PbSe (-84 meV GPa(-1)). We used again the hypothesis of a linear variation of the carrier effective masses with pressure in order to fit this experimental variation quantitatively.
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