A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the populatio...A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the population inversion can be formed between the valence band and the localized states produced from the surface bonds. The nano-laser belongs to the emission of type Ⅱ. The peaks of stimulated emission are observed at 605 nm and 693 nm. Through the micro-cavity of nano-laser, a full width at half maximum of the peak at 693 nm can reach to 0.5 nm. The theoretical model and the experimental results indicate that it is a necessary condition for setting up nano-laser that the smaller size of nano-clusters (d<3 nm) can make the localized states into band gap below the conduction band opened and the states of conduction band become the pumping level of nano-laser. The emission energy of nano-laser will be limited in the range of 1.7～2.3 eV generally due to the position of the localized states in gap, which is good in agreement between the experiments and the theory.展开更多
The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized ...The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized levels in band gap and its bonding energy is shallower than that on facet. The red-shifting of PL spectra on smaller silicon quantum dots can be explained by curved surface effect. Experiments demonstrate that silicon quantum dots are activated for emission due to the localized levels provided in curved surface effect.展开更多
基金Support from the National Natural Science Foundation of China ( Grant No.10764002,60966002,11264007)the National Key Laboratory of Surface Physics in Fudan University
文摘A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the population inversion can be formed between the valence band and the localized states produced from the surface bonds. The nano-laser belongs to the emission of type Ⅱ. The peaks of stimulated emission are observed at 605 nm and 693 nm. Through the micro-cavity of nano-laser, a full width at half maximum of the peak at 693 nm can reach to 0.5 nm. The theoretical model and the experimental results indicate that it is a necessary condition for setting up nano-laser that the smaller size of nano-clusters (d<3 nm) can make the localized states into band gap below the conduction band opened and the states of conduction band become the pumping level of nano-laser. The emission energy of nano-laser will be limited in the range of 1.7～2.3 eV generally due to the position of the localized states in gap, which is good in agreement between the experiments and the theory.
基金Support from the National Natural Science Foundation of China (Grant No.60966002,11264007)the National Key Laboratory of Surface Physics in Fudan University
文摘The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized levels in band gap and its bonding energy is shallower than that on facet. The red-shifting of PL spectra on smaller silicon quantum dots can be explained by curved surface effect. Experiments demonstrate that silicon quantum dots are activated for emission due to the localized levels provided in curved surface effect.
