Disorder-tuned conductivity in amorphous monolayer carbon

Huifeng Tian, Yinhang Ma, Zhenjiang Li, Mouyang Cheng, Shoucong Ning, Erxun Han, Mingquan Xu, Peng Fei Zhang, Kexiang Zhao, Ruijie Li, Yuting Zou, Pei Chi Liao, Shulei Yu, Xiaomei Li, Jianlin Wang, Shizhuo Liu, Yifei Li, Xinyu Huang, Zhixin Yao, Dongdong DingJunjie Guo, Yuan Huang, Jianming Lu, Yuyan Han, Zhaosheng Wang, Zhi Gang Cheng, Junjiang Liu, Zhi Xu, Kaihui Liu, Peng Gao, Ying Jiang, Li Lin, Xiaoxu Zhao, Lifen Wang, Xuedong Bai, Wangyang Fu, Jie Yu Wang, Maozhi Li, Ting Lei, Yanfeng Zhang, Yanglong Hou, Jian Pei, Stephen J. Pennycook, Enge Wang, Ji Chen*, Wu Zhou*, Lei Liu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)

Abstract

Correlating atomic configurations—specifically, degree of disorder (DOD)—of an amorphous solid with properties is a long-standing riddle in materials science and condensed matter physics, owing to difficulties in determining precise atomic positions in 3D structures1–5. To this end, 2D systems provide insight to the puzzle by allowing straightforward imaging of all atoms6,7. Direct imaging of amorphous monolayer carbon (AMC) grown by laser-assisted depositions has resolved atomic configurations, supporting the modern crystallite view of vitreous solids over random network theory8. Nevertheless, a causal link between atomic-scale structures and macroscopic properties remains elusive. Here we report facile tuning of DOD and electrical conductivity in AMC films by varying growth temperatures. Specifically, the pyrolysis threshold temperature is the key to growing variable-range-hopping conductive AMC with medium-range order (MRO), whereas increasing the temperature by 25 °C results in AMC losing MRO and becoming electrically insulating, with an increase in sheet resistance of 109 times. Beyond visualizing highly distorted nanocrystallites embedded in a continuous random network, atomic-resolution electron microscopy shows the absence/presence of MRO and temperature-dependent densities of nanocrystallites, two order parameters proposed to fully describe DOD. Numerical calculations establish the conductivity diagram as a function of these two parameters, directly linking microstructures to electrical properties. Our work represents an important step towards understanding the structure–property relationship of amorphous materials at the fundamental level and paves the way to electronic devices using 2D amorphous materials.

Original languageEnglish
Pages (from-to)56-61
Number of pages6
JournalNature
Volume615
Issue number7950
DOIs
Publication statusPublished - 2 Mar 2023

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