Explanation

When the particle size is comparable to the de Broglie wavelength, the coherence wavelength and the exciton radius of the electron, the electron is localized in the nanoscale space, the electron transport is limited, the mean free path of electrons of the electron is significantly shortened, and its localization and coherence are enhanced, which is called the quantum confinemem effect. For quantum dots or nanocrystal, when the particle size is equal to or smaller than the Wannier exciton Bohr radius, it is in a strongly confined region, and it is easy to form exciton to generate exciton absorption bands. With the decrease of particle size, the absorption coefficient of exciton band increases and strong absorption of exciton appears. Due to the quantum confinemem effect, the lowest energy of the exciton moves towards the high energy direction, that is, blue shift. The latest report indicates that NEC in Japan has successfully prepared quantum dot arrays and deposited nano island like quantum dot arrays on the substrate. When the quantum dots is excited by laser irradiation, the quantum dots emits blue light, indicating that the quantum dots does have quantum confinemem effect.

Classification