Optical Properties of Silicon Quantum Dots

摘要

A first-principles study of the optical properties of silicon quantum dots (QDs) with different diameters(dQD)is presented in this paper. Silicon QDs consisting of 10-220 Si atoms (dQD=6-20(A))with full termination of the Si interface with H are investigated in detail. The results show that both the band gap and the absorption spectrum of silicon QDs are size-dependent. For silicon QDs withdQD=6-20(A)),as the decreases, the band gap increases, and a considerable blue-shift in the absorption spectrum is occurred. This unique property can be used to extend the absorption spectrum of the solar cell by mixing in QDs with different sizes. Therefore, the full spectrum of the sunlight may be utilized more efficiently.