石墨烯纳米间隙电极的构筑及其在光探测器中的应用

With the ongoing development of the matter study, nanogap electrodes are playing a more and more important role in examining and characterizing the material properties at the nanoscale. Many different ways have been developed to fabricate nanogap electrodes used for examining the material properties. As for graphene, one kind of ideal electrode materials, the current reported gap of graphene electrodes fabricated via “top-down” strategy can only go down to 70 nm. Via “bottom-up” approach, in this proposal, we aim to directly grow graphene-based nanogap electrodes with the tunable channel length and with the shortest length of about several nm on copper foil by chemical vapor deposition method. As a demo, the photodetectors based on the as-grown graphene-based nanogap electrodes will be presented. The relatively long response time of the currently fabricated photodetectors based on one-dimensional material is probably resulted from the long transport time of the photo-generated carriers due to the long channel used in the photodetectors. In this proposal, we will combine the II-VI nanowires with the as-grown graphene-based nanogap electrodes to fabricate the nanowire-based photodetectors with nanoscale channel length and consequently superior photo-response performance. We believe that this method developed in this proposal will pay a way for fabricating the graphene nanogap electrodes and the nanowire photodetectors with superior photo-response performance based on the nanogap electrodes.

随着物质研究的不断深入，利用纳米间隙电极在纳米尺度上来分析检测材料的性能变得越来越重要。对于石墨烯这一理想电极材料，当前利用“自上而下”的策略所构筑的石墨烯电极间隙只能到70纳米，还不够窄。本项目中，申请人提出“自下而上”策略，采用chemical vapor deposition方法在铜箔上直接生长出沟道长度可调的并且最短沟道长度为几纳米的石墨烯纳米间隙电极，并以光探测器为例来阐述其应用。一维纳米材料所构筑的探测器光响应时间还较长，这可能是由于沟道长度较大使得光生载流子传输时间过长所导致的。申请人将直接生长的石墨烯纳米间隙电极与ZnS，CdS和CdSe等II-VI族纳米线结合起来，制作出沟道长度为纳米尺度的具有优异光响应性能的光探测器。本项目发展的CVD生长石墨烯纳米间隙电极和基于该电极构筑光探测器的方法将为石墨烯纳米间隙电极和具有优异光响应性能的光探测器的构筑提供了一种有效途径。

光探测器在军事和国民经济的各个领域有广泛用途，包括空间通讯，臭氧层监测、紫外辐射监控和遥感等。本项目中，申请人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，在此基础上构筑了100 nm左右的短沟道具有超高灵敏度10^9 A/W的石墨烯/半导体薄膜光探测器，最后探索了石墨烯/半导体薄膜光探测器在图像传感器中的潜在应用。本项目所发展的基于石墨烯/族半导体薄膜复合结构的高性能光探测器的构筑方法为高性能光探测的研究提供了有效途径。