Моделирование уровней размерного квантования Si-нанокристаллов в матрице SiO-=SUB=-2-=/SUB=-: подбор параметров эмпирического метода сильной связи

Abstract

AbstractThe problem of the optimal choice of parameters of the empirical tight-binding method to simulate the quantum-confined levels of Si nanocrystals embedded into an amorphous SiO_2 matrix is studied. To account for tunneling from nanocrystals to SiO_2, the amorphous matrix is considered as a virtual crystal with a band structure similar to that of SiO_2 β-cristobalite and with a lattice constant matched to the lattice constant of bulk Si. The electron density distributions in k space for electrons and holes quantum-confined in a Si nanocrystal in SiO_2 are calculated in a wide energy region, which provides a means to see clearly the possibility of the existence of efficient direct optical transitions for hot electrons at the upper quantum-confined levels.