纳米金属Tm的电子浓度研究

电子浓度是与金属的宏观特性相关的重要参数.反射光谱和霍尔效应分别是得出电子浓度和载流子浓度的基本实验.两个纳米稀土金属铥Tm样品(样品1,平均粒径100nm,样品2,平均粒径10nm)的红外---紫外反射光谱实验表明,金属铥Tm表面的反射光学性质具有金属的特征,6s能带具有与碱金属相近的电子浓度n_p,数值分别为2.434×10²⁸/m³和1.701×10²⁸/m³.而样品的霍尔效应实验测得金属Tm的载流子是电子-空穴型的,载流子浓度n_H仅分别为8.032×10²⁴/m³和7.679×10²⁴/m³,仅仅是费米面附近的电子-空穴状态.另外,铥Tm的电导率比半导体的大3个量级.晶粒纳米化使电子浓度n_p减小,电导率σ减小,载流子浓度减小,而霍尔系数R_H增大.

Study of electron density of nanostructure metal Tm

Electron density is an important parameter for the macroscopic properties of metal. The reflectance spectrum measurement and the Hall Effect measurement are basic experiments for obtaining electron density and carrier density. Two samples (sample 1:100 nm, sample 2:10 nm) of nanostructure block rare earth metal Tm are studied. Their reflectivity spectra show that the surface reflection of Tm metal possess metallic optical properties in a region of infrared-ultraviolet, the electronic densities n_p of 6s band are 2.434× 10²⁸/m³ and 1.701×10²⁸/m³ similar to that of alkali. The carriers measured by Hall Effect experiment are of cavity tipe in the two samples, and the carrier densities n_H are 8.032×10²⁴/m³ and 7.679×10²⁴/m³ respectively. They are only states near the Fermi surface. In addition, the conductance of Tm block is three orders of magnitude higher than one of semiconductor. The grain nanostructurization makes electronic density n_p, conductance σ, and carrier density n_H decrease, but Hall coefficient R_H increase.