When the size of the nanocrystals decreases to the exciton Bohr radius, the energy level becomes discrete from the continuum, and the energy gap increases as the crystal boundary significantly modifies electron distribution, showing a quantum confinement effect. 当微粒尺寸减小至激子的玻尔半径时,由于晶界改变了电子分布状态,相应的电子能态从连续的能带变为分立的能级结构,使带隙变宽,表现出量子限域效应。
The exciton Bohr radius of Ge is far greater than that of silicon, indicating that obvious quantum size effect will appear in Ge. Ge的激子玻尔半径远大于硅,表明其具有更为显著的量子尺寸效应。