Influence of capping layer thickness on the polarization of photoluminescence of CdSe/ZnSe quantum dots grown by metalorganic chemical vapor phase deposition |
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Authors: | X B Zhang S K Hark |
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Affiliation: | (1) Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong |
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Abstract: | The polarization of the photoluminescence (PL) of self-assembled CdSe quantum dots (QDs), grown by metalorganic chemical vapor
phase deposition, was measured. From the (001) surface, the PL was found preferentially polarized in the
direction, while from the
cleaved surface in the 001] direction. The polarization of PL depends strongly on the ZnSe capping layer thickness and the
PL energy. With an increase in ZnSe coverage, the intensity ratio
was found to increase first, then decrease after the coverage is thicker than a critical value. Moreover, such a critical
thickness is smaller for larger QDs (lower PL energies). Possible origins of the PL polarization are discussed. We suggest
that besides the quantum confinement effects, the strain field in the QDs also plays an essential role in the observed polarization
of PL. |
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Keywords: | Polarization photoluminescence CdSe quantum dots capping layer thickness MOCVD |
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