Stable alkali halide vapor assisted chemical vapor deposition of 2D HfSe2 templates and controllable oxidation of its heterostructures  

作　　者：Wenlong Chu Xilong Zhou Ze Wang Xiulian Fan Xuehao Guo Cheng Li Jianling Yue Fangping Ouyang Jiong Zhao Yu Zhou 

机构地区：[1]School of Physics,Hunan Key Laboratory of Nanophotonics and Devices,Central South University,Changsha 410083,China [2]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China [3]CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing100190,China [4]Department of Applied Physics,The Hong Kong Polytechnic University,Kowloon,Hong Kong,China

出　　处：《Frontiers of physics》2024年第3期29-38,共10页物理学前沿（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.U23A20570 and 51902346);the Science and Technology Innovation Program of Hunan Province(“HuXiang Young Talents”,Grant No.2021RC3021);the Key Project of the Natural Science Program of Xinjiang Uygur Autonomous Region(Grant No.2023D01D03);the Natural Science Foundation of Hunan Province(Grant No.2021JJ40780).

摘　　要：Two-dimensional hafnium-based semiconductors and their heterostructures with native oxides have been shown unique physical properties and potential electronic and optoelectronic applications.However,the scalable synthesis methods for ultrathin layered hafnium-based semiconductor laterally epitaxy growth and its heterostructure are still restricted,also for the understanding of its formation mechanism.Herein,we report the stable sublimation of alkali halide vapor assisted synthesis strategy for high-quality 2D HfSe_(2) nanosheets via chemical vapor deposition.Single-crystalline ultrathin 2D HfSe_(2) nanosheets were systematically grown by tuning the growth parameters,reaching the lateral size of 6‒40μm and the thickness down to 4.5 nm.The scalable amorphous HfO_(2)and HfSe_(2)heterostructures were achieved by the controllable oxidation,which benefited from the approximate zero Gibbs free energy of unstable 2D HfSe_(2) templates.The crystal structure,elemental,and time dependent Raman characterization were carried out to understand surface precipitated Se atoms and the formation of amorphous Hf−O bonds,confirming the slow surface oxidation and lattice incorporation of oxygen atoms.The relatively smooth surface roughness and electrical potential change of HfO_(2)−HfSe_(2) heterostructures indicate the excellent interface quality,which helps obtain the high performance memristor with high on/off ratio of 105 and long retention period over 9000 s.Our work introduces a new vapor catalysts strategy for the synthesis of lateral 2D HfSe_(2) nanosheets,also providing the scalable oxidation of the Hf-based heterostructures for 2D electronic devices.

关 键 词：chemical vapor deposition HfSe_(2)−HfO_(2) nanoelectronics 

分 类 号：TB383[一般工业技术—材料科学与工程]