OBSERVATION OF THE QUASI-DIRECT RECOMBINATION IN NANOCRYSTALLINE SILICON DOTS BY REDUCING THE CORE DIAMETER

摘要

Photoluminescence (PL) spectra of nanocrystalline-Si (nc-Si) dots with various core diameters are investigated. The PL intensity of the nc-Si dots drastically increases with decreasing core diameter when the core diameter is less than the exciton Bohr radius of bulk Si. Because the amount of the deposited nc-Si dots on each sample is the same, this enhancement of the PL intensity can be explained by the quasi-direct no-phonon-assisted recombination in the nc-Si dot, which is caused by the relaxation of the κ-conservation rule.