碱土族金属掺杂对C_(60)薄膜的电子结构与性质的影响

Influence of Alkali-Earth Metal Doped on Structure and Conductivity of C_(60) Thin Films

将Ｓｎ粉末和Ｃ６０粉末共同蒸发获得碱土族金属掺杂的Ｃ６０薄膜样品,与未掺杂的纯Ｃ６０样品一起进行扫描电镜、紫外可见吸收光谱和电阻随温度变化特性的测量,分析比较掺杂对薄膜样品的组成、结构和性质的影响．结果显示,掺锡后组成薄膜的纳米颗粒略有增大并突出表面,使薄膜的电子发射阈值降低;掺入的Ｓｎ原子在禁带中形成杂质能级,使电子吸收跃迁由原来的直接跃迁变为间接跃迁,导电性也由原来的绝缘体变为Ｎ型半导体．

Alkali-earth metal doped C60 thin film is produced by evaporating C60 powder together with Sn powder. We analyze the influence of doping on component, structure and conductivity of C60 thin film by measuring the SEM, UV optical absorption and resistivity change with temperature of the film. The results show that after doping the tiny drops forming the film stick out of the surface, and the size of the drops increases slightly. So the electron emission threshold value of the film will lower. The Sn atom doped form the impurity level in the forbidden band. So the electron absorption transition changed from directly to indirectly, and the electrical conductivity changed too from insulator to n-type semiconductor.