悬空单晶MoS2场效应管重金属离子传感器基础研究

A facile, low-cost, and rapid heavy metal ion detection technique is vital important and highly desired. In this project we propose to develop suspended single-crystalline MoS2 field-effect transistor (FET) sensors to meet this requirement. MoS2 sensors reported so far are based on poly-crystalline film which is anchored on supporting substrate. Besides, Schottky barrier is formed between MoS2 and metal electrode. The grain boundary, substrate scattering, and contact barrier not only drastically deteriorate the performance of MoS2 sensors, but also mask the sensing mechanism of intrinsic MoS2. A novel MoS2 sensor is proposed to solve these problems. Firstly, in order to avoid grain boundary in fabricated devices, we propose an approach of addressable single-crystalline MoS2 arrays growth by using pre-patterned seeds to control the nucleation. The growth mechanism will be systematically investigated. Secondly, suspended MoS2 beam structure is proposed to eliminate the influence of substrate scattering, and the suspension technique of MoS2 nanostructure will be investigated. Thirdly, MoS2 phase transformation (from semiconducting 2H phase to metallic 1T phase) will be carried out to reduce the contact barrier height at metal electrodes. Moreover, ionophore will be applied to improve the selectivity of MoS2 FET sensors. Based on the proposed novel MoS2 sensors, we will explore the sensing mechanism of intrinsic MoS2 theoretically and experimentally, providing a solid scientific foundation for MoS2 sensing technique. The performance of MoS2 FET in new regimes for heavy metal ion detection (lead, cadmium, mercury, and arsenite) will be systematically investigated in order to exert the potential of MoS2 as a sensing material. As a result, high performance novel MoS2 ion sensors will be realized. This project paves the way for facile, low-cost, and rapid heavy metal ion detection technique. It is also important for solving basic scientific problems in MoS2 field, including grain boundary defect.

针对重金属检测领域对便捷、低成本、快速的传感技术的迫切需求，本项目提出悬空单晶MoS2场效应管传感器阵列的总体构想。目前的传感技术中，晶界缺陷、基底散射和接触势垒阻碍了MoS2材料特性充分发挥，并掩盖了MoS2传感机理。为此，本项目提出植入晶核法，研究通过新的生长机理控制单晶MoS2生长位置，解决晶界缺陷问题；提出并研究MoS2敏感材料悬空技术，消除基底散射；研究将1T晶格结构MoS2引入离子传感器电极接触部分，解决接触势垒问题；此外，通过离子载体提升MoS2选择性。借助以上独特的材料制备方法和器件结构，揭示MoS2传感机理，为MoS2传感技术提供理论基础；探索MoS2在新的传感模式下对铅、镉、汞、砷的传感特性，以期更大限度地发挥MoS2材料的潜能。最终获得高性能新型MoS2传感器。本项目不仅为实现便捷、低成本、快速的重金属检测技术奠定基础，且有助于解决MoS2领域晶界缺陷等基础科学问题。

针对重金属检测领域对便捷、低成本、快速的传感技术的迫切需求，本项目提出悬空单晶MoS2场效应管传感器阵列的总体构想。目前的传感技术中，晶界缺陷、基底散射和接触势垒阻碍了MoS2材料特性充分发挥，并掩盖了MoS2传感机理。为此，本项目提出植入晶核法，研究通过新的生长机理成功实现控制单晶MoS2生长位置，为后续器件加工避开晶界奠定基础，解决了晶界缺陷难题；提出并解决了MoS2敏感材料悬空技术，消除了基底散射；发现二硫化钼接触势垒变化规律，极大降低了金属/二硫化钼接触电阻，解决了二硫化钼接触势垒问题；此外，通过离子载体提升MoS2选择性。借助以上独特的材料制备方法和器件结构，揭示了MoS2本征传感机理，为MoS2传感技术提供理论基础；探明了MoS2在新的传感模式下对重金属离子的传感特性，更大限度地发挥了MoS2材料的潜能。最终获得高性能新型MoS2传感器。本项目不仅为实现便捷、低成本、快速的重金属检测技术奠定基础，且有助于解决MoS2领域晶界缺陷等基础科学问题。在本项目资助下，在J. Mater. Chem. A，Nano Energy，ACS Appl. Mater. Interfaces等国际著名期刊发表SCI论文10篇，5篇影响因子>9，1篇ESI高被引论文，1篇J. Mater. Chem. A（IF：12.7）封底论文。获授权国家发明专利1项。研究成果获得P. Samori（欧洲科学院院士）、Y. B. Hahn（韩国科学院院士）、K. Ariga（东京大学教授）等本领域著名学者高度评价。研制的二维材料离子传感器在中国水科院等机构获得试用。