石墨烯基底上II-VI族合金纳米棒阵列的制备及光电性能研究

In terms of the applications for one dimensional (1D) II-VI semiconductors, it is of great importance to fabricate the nanodevices with tunable and predetermined optoelectronic properties. The alloying of the binary II-VI semiconductors, namely energy band engineering, is one kind of effective strategy. 1D alloyed II-VI semiconductors with tunable but non-predetermined compositions can be synthesized via the currently used thermal evaporation method. Moreover, it is still quite difficult to obtain 1D alloyed II-VI arrays through the thermal evaporation approach, which will hamper the nanodevice fabrication based on 1D alloyed II-VI semiconductors. In this proposal, we aim to develop a novel strategy to address this challenge, taking ZnSxSe1-x as an example. First, the ZnS/ZnSe heterostructure nanorod arrays with the fixed ZnS-ZnSe ratio are generated on graphene substrate via e-beam evaporation in the combination with the polystyrene nanosphere lithography. Subsequently, after annealing with the proper conditions, they are expected to turn into single-crystal alloyed ZnSxSe1-x nanorod arrays with the same ZnS-ZnSe ratio as that in ZnS/ZnSe heterostructure, and the composition of alloyed ZnSxSe1-x nanorods can be tuned by changing the ZnS-ZnSe ratio in ZnS/ZnSe heterostructure. That is, the alloyed II-VI nanorod arrays with the tunable and predetermined compositions and properties can be obtained. We believe that this general strategy developed in this proposal will pay a way for fabricating the nanodevice with the tunable and predetermined optoelectronic properties based on 1D alloyed II-VI semiconductors.

对于一维II-VI族半导体纳米材料的应用来说，实现具有可调且可预定光电性能的纳米器件构筑极为重要。二元II-VI族半导体的合金化即能带工程是一个有效手段。通过当前制备一维II-VI族合金纳米材料的热蒸发方法只能实现成分可调但不可预定，并且很难获得阵列，限制了器件构筑。在本项目中，申请人以ZnSxSe1-x合金纳米棒阵列为例提出一种全新方法：结合聚苯乙烯模板技术，在石墨烯基底上通过蒸镀方法得到具有特定成分比的ZnS和ZnSe异质结纳米棒阵列，再通过退火手段利用外延生长方法获得和异质结成分比相同的ZnSxSe1-x合金纳米棒阵列，并通过改变异质结中两种材料的成分比，最终实现II-VI族合金纳米棒成分和性能的可调且可预定以及阵列构筑。本项目发展的在石墨烯基底上外延生长II-VI族合金纳米棒阵列的策略为实现具有可调且可预定光电性能的一维II-VI族合金纳米材料器件提供了一种有效途径。

薄膜材料在光探测器阵列的构筑方面具有很大优势，因为它的制备和加工工艺与传统互补金属氧化物半导体(CMOS)电子学相兼容。然而，纳米晶薄膜较低的载流子迁移率导致较差的光响应性能。针对这一难题，申请人提出了以下两个思路。一、大尺寸晶粒半导体薄膜的生长及其光探测器阵列的构筑。二、纳米晶半导体与高载流子迁移率石墨烯异质结光探测器的构筑。在实现高质量单层石墨烯的生长和转移的基础上，将具有超高载流子迁移率的石墨烯薄膜与在光照下能获得光生载流子的半导体薄膜的结合，发展了基于石墨烯/族半导体薄膜复合结构的高性能光探测器构筑的普适方法。