Structure and Electrical Property of CuInS₂ Thin Films Deposited by DC Reactive Magnetron Sputtering

采用直流反应磁控溅射技术在玻璃基底上制备了太阳电池用 CuInS₂ 薄膜. 以 X 射线能量色散谱仪、扫描电 镜、X 射线衍射仪、冷热探针和霍尔效应测试系统对薄膜进行了表征. 结果表明, 薄膜成分可通过调整 Cu 靶和 In 靶的功率比 P_Cu/P_In 来进行调控; 而薄膜形貌则取决于靶功率比和薄膜的成分. 随着 P_Cu/P_In 的增大, 薄膜物相由富 铟相向 CuInS₂ 转变. 对于 CuInS₂ 薄膜, 提高铜铟原子比[Cu]/[In]可改善薄膜的结晶质量. 但当薄膜富铜时, 过高的 [Cu]/[In]又会导致薄膜结晶质量的下降. 当 CuInS₂ 薄膜为富铜与略微贫铜时, 其导电类型为 P 型; 且载流子浓度随 [Cu]/[In]增加而增大, 并远高于其它贫铜薄膜. CuInS₂ 薄膜的载流子迁移率明显高于富铟相薄膜; 且随着[Cu]/[In] 的提高, CuInS₂ 薄膜的载流子迁移率呈上升趋势, 而电阻率则迅速下降. CuInS₂ thin films for solar cells were prepared on the glass substrate by DC reactive magnetron sputtering technique. Produced films were characterized by EDS, SEM, XRD, hot point probe and Hall electrical measurement. The results suggest that the composition of the films are determined and controlled by the power ratio of copper target and indium target, while the morphology of thin films depends on the composition of thin films and target power ratio. As the atomic ratio [Cu]/[In] increases, the film phases transform from the In-rich phases to CuInS₂ phases. Although increasing atomic ratio [Cu]/[In] can improve the crystalline quality of CuInS₂ thin films, high [Cu]/[In] in Cu-rich thin films will lead to the declination of crystalline quality. Cu-rich or slightly Cu-poor CuInS₂ films show P-type conducting. With the increase of the atomic ratio [Cu]/[In], the carrier concentration and the carrier mobility of CuInS₂ thin film raises, but the resistivity declines sharply. It is also found that and the carrier concentration and carrier mobility of the Cu-rich CuInS₂ films are much higher than that of Cu-poor ones.