多层范德华异质结的金属诱导定点构筑及其光电性能研究

Graphene-like transition metal dichalcogenides (TMD) is a layered material with certain band gap. If different TMD crystals were stacked vertically for fabricating Van der Waals heterojunction, which will produce many novel physical phenomena and form unique function devices. However, there are still key scientific problems that nucleation sites are not controllable during the growth and only two layers TMD materials can be stacked vertically for forming heterojunction, and artificial van der Waals crystal with multilayer vertically stacked TMD materials is still unable to be effectively fabricated. This project is proposed new ideas of metal induced growth to solve the problem: arrays of metal point with catalysis, used as the induced growth point, are fabricated on the substrate by photolithography, and micron sized TMD crystals can be induced and grown in the metal point by chemical vapor deposition method. Then, microstructure with confinement effect is prepared via using the grown TMD crystal as template during corrosion process. Fanally, van der Waals heterostructure with multilayer vertically stacked TMD materials will be artificially fabricated at controlled locations under the effect of confinement effect and multiple metal inductions. During the project implementation, we will analysize the influences of metal type, reaction atmosphere, air pressure and other factors on the crystal growth, understand nucleation mechanism of metal induced growth, and establish the growth model of two-dimensional TMD crystal, and then form a technical growth route of vertically stacked heterojunction arrays based on TMD materials. Which are pretty important for scientific significance and potential application prospect.

过渡金属硫化物(TMD)是类石墨烯的具有带隙的层状材料。若将不同的二维TMD垂直堆垛形成范德华异质结晶体,有望产生许多新奇的物理现象和具有独特功能的器件。然而，目前仍然存在生长时形核位置的不可控和形成垂直堆垛异质结时仅局限于两层垂直堆垛的关键科学问题，多层垂直堆垛的范德华异质结超晶格仍然无法有效实现。本项目提出了解决问题的金属诱导定点生长新思路：采用具有催化作用的金属作为生长的诱导点，通过光刻技术在基片上形成金属阵列，再使用化学气相沉积法，在金属点处诱导生长微米级的TMD晶体，然后以该晶体自身为模板构建限域效应的微结构，结合金属多次诱导作用,实现定点生长多层垂直堆垛的二维材料范德华异质结。分析金属类型、反应气氛和气压等因素对晶体生长的影响，理解金属诱导成核机制，建立二维TMD晶体的生长模型，形成一种基于TMD材料垂直堆垛异质结阵列构筑的技术路线，该研究具有重要的科学意义和潜在的应用前景。

过渡金属硫化物（TMDCs）是类石墨烯的具有带隙的二维层状材料，在光电探测、光伏等方面有广阔的应用前景。以二维TMDCs材料在研制新型光电探测器件中的应用为背景，项目研究了二维过渡金属硫化物化学气相沉积法生长的关键控制因素，设计简易可信的用于大尺寸TMD单晶生长的微纳反应腔，在SiO2基底上实现亚毫米TMD二维单晶的宏量生长；利用金属的诱导作用，研究二维晶体的图形化生长，探索二维TMDCs晶体图形化构筑的普适路线，构筑基于MoS2、WSe2等二维TMDCs晶体的光电探测器阵列；利用异质外延原理，六方对称的 TMD控制非二维材料的取向生长，研究具有精确对称性控制的 TMDCs/XN 垂直异质结的通用合成方法。这些对开拓二维材料器件批量构筑的新技术、新方法，具有重要的科学意义和潜在的应用前景。同时项目完成过程中，发表学术论文11篇（SCI 论文8篇,第一标注7篇，第二标注1篇，第三标注3篇），其中包括国际权威期刊Nanoscale 1篇；申请专利4项，授权专利2项（授权发明专利和实用新型专利各1项），超额完成了任务书中的主要考核指标。