非晶化与量子限域效应

当材料尺度减小到几个纳米时，材料内部电子结构会表现为分立能级，这就是所谓的量子限域效应。通过晶态和非晶Pd纳米颗粒的单电子隧穿实验发现，在晶态Pd颗粒中能观察到量子限域效应，而在同样大小的非晶Pd颗粒中却没有观察到。考虑到有序／无序结构的静态效应并结合电子散射等动态效应，解释了非晶Pd颗粒实验中没有观察到量子限域效应的原因。这一结果表明，尺寸减小并不足以使纳米体系表现量子行为，原子结构有序度对于决定纳米体系表现经典行为或量子行为具有同等重要作用。

Amorphization of metal nanoparticles and the quantum confinement effect

When a metal particle is reduced to several nanometers in diameter, it will exhibit an electronic structure with discrete energy levels due to the quantum confinement effect. The current|voltage ( I | V ) measurements based on single|electron spectroscopy show fine structures in the I|V curves of crystalline Pd nanoparticles caused by the discrete energy levels, while amorphous Pd nanoparticles of similar particle size have I-V curves with equidistant Coulomb staircases. The suppression of the quantum confinement effect in the amorphous state results from the combination of a static effect due to the disorder and a dynamic effect caused by electron|electron scattering. This indicates that the degree of the atomic order of a nanoparticle plays an equally important role as its size in determining its quantum or classical nature,and causes the suppression of quantum confinement in the amorphous particle.