二维单层半导体相2H-MoTe2的可控制备及光电性质研究

Monolayer 2H-MoTe2 is a direct bandgap semiconductor, its superior electrical, optical and unique phase transition properties, shows great potential application in nanoelectronics, optoelectronic and other fields. Controlled synthesize of monolayer 2H-MoTe2 is the fundamental issues for its further broaden application. By combining the monodispersity of sapphire substrate and van der walls epitaxy, here we offered a new approach to control growth of monolayer 2H-MoTe2 single crystal with large area on c-plane sapphire substrate by chemical vapor deposition. Due to the monodispersity of sapphire substrate, monolayer Mo precursor could be modified on the substrate; Induced by the van der Waals force between the surface of c-plane sapphire substrate and materials, the threefold symmetry monolayer 2H-MoTe2 will epitaxial growth on the substrate, and with this approach to realize the preparation of large area, high-quality controllable monolayer 2H-MoTe2 material finally. Then, studying the stable mechanism of Te atoms of as-grown monolayer 2H-MoTe2 via modified compounds, to develop an undamaged transfer method finally. In addition, the electronic and near infrared photo-response properties will be investigated, which can be provide valuable information and idea for designing and constructing the near infrared photo-detection model device. At last, this proposal is aimed to solve key problems in phase-controlled growth of monolayer 2H-MoTe2 and undamage transfer.

半导体相单层2H-MoTe2晶体优异的光电性质及易相变特性使其在纳电及光电器件等领域有巨大的应用前景。但大面积单层2H-MoTe2单晶的可控制备是制约其基础和应用研究发展的瓶颈。本项目提出将氧化铝表面单分散技术与范德华外延技术相结合,通过化学气相沉积法在c-plane氧化铝基底上可控制备大面积单层2H-MoTe2单晶。利用氧化铝表面的单分散技术,实现基底表面单分子层钼源的加载;利用基底与材料的范德华作用力,诱导三重对称的单层2H-MoTe2在基底表面外延生长,实现大面积、高质量单层2H-MoTe2单晶的可控制备。研究修饰化合物对单层2H-MoTe2中Te原子稳定性的作用机制,实现单层2H-MoTe2的无损转移。研究单层2H-MoTe2基器件的电学与近红外光电响应等性质,为构筑其近红外光电探测器件提供理论依据和技术支持。该课题将解决单层2H-MoTe2单晶的可控制备和无损转移等关键科学问题。

二维无机层状材料优异的电学和光电性质使其在晶体管、光电探测器等领域有巨大的应用前景。而大尺寸单晶及晶圆级的可控制备是制约其基础和应用研究发展的瓶颈。本项目主要的研究内容和成果有：①材料可控制备方面：利用分子筛辅助控制释放Mo前驱体，获得了形貌、尺寸均匀可控的单晶1T'-MoTe2；借助于氧化铝衬底的单分散效应，采用化学气相沉积法制备了13种严格单层过渡金属硫族化合物(TMDs)及其合金的晶圆级高通量制备；发展了空间限域的涡流化学气相沉积法，在柔性导电膜上合成了高质量ReS2/ReO2异质结阵列；实现了高晶格应力单晶MoxYb1-xS2合金的可控制备；使用多金属氧酸盐的金属有机骨架辅助置换策略，制备了三维MoO2@孔状碳限域Pt催化剂；利用Pt薄膜硫化法制备了大面积、高质量的PtSe2连续薄膜；通过弱相互作用无氢电化学插层策略，实现了超大尺寸薄层黑磷单晶的规模化制备。②界面调控方面：发现了TMDs表面硫原子物理吸附的表面限域效应，进而实现了晶圆级TMDs表面亚纳米硫原子膜的均匀覆盖，显著提升了其在空气环境下光学和电学性能的长期稳定性；提出了一种电化学插层和原位电化学金属沉积相结合的方法，高通量制备了超稳定Au/FL-BP晶体，并实现了恶劣环境下器件稳定性的显著提升(超过45天)。③应用探索方面：利用角分辨偏振光学衬度谱研究了1T'-MoTe2晶体各向异性光学性质，发展出了晶界的无损识别方法；构筑了单层MoxYb1-xS2合金基高迁移率(101.3 cm2V-1s-1)和宽光谱响应器件(532-1850 nm)；基于PtSe2纳米墙薄膜与三维MoO2@孔状碳限域Pt催化剂，在较低起始电位下获得了高催化析氢性能；基于Au/FL-BP、1T'-MoTe2 等光电晶体管器件，实现了高性能宽光谱(532-2200 nm)光电探测。本项目的部分成果有助于突破限制二维材料可控制备的问题，加快二维材料在电子及光电探测领域的基础和应用研究步伐。