| XU Dai,LU Jiaqi,LIU Lusheng,YANG Yuechao,GUAN Yin,HUANG Nan,JIANG Xin,YANG Bing.One-step Preparation of Diamond/Carbon Nanowalls Films with High Electrical Conductivity Based on Electron Field Emission[J],54(6):194-205 |
| One-step Preparation of Diamond/Carbon Nanowalls Films with High Electrical Conductivity Based on Electron Field Emission |
| Received:April 16, 2024 Revised:May 16, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.06.018 |
| KeyWord:diamond graphite composite film interlayer electron field emission chemical vapor deposition |
| Author | Institution |
| XU Dai |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China;School of Materials Science and Engineering, University of Science and Technology of China, Shenyang , China |
| LU Jiaqi |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China;School of Materials Science and Engineering, University of Science and Technology of China, Shenyang , China |
| LIU Lusheng |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| YANG Yuechao |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| GUAN Yin |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| HUANG Nan |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China;School of Materials Science and Engineering, University of Science and Technology of China, Shenyang , China |
| JIANG Xin |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| YANG Bing |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China;School of Materials Science and Engineering, University of Science and Technology of China, Shenyang , China |
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| Abstract: |
| The improvement of the electrical conductivity of the film and the interfacial electrical conductivity between the film and substrate is crucial for optimizing the electron field emission performance of diamond films. The work aims to present a one-step method for preparing diamond/carbon nanowalls (D/CNWs) films with high electrical conductivity and no high-resistance interlayer, so as to enhance the electron field emission performance of diamond films. Herein, two types of high electrically conductive diamond composite films, including diamond/graphite (D/G) nanosheets films and diamond/carbon nanowalls (D/CNWs) films, were prepared in a one-step through microwave plasma enhanced chemical vapor deposition (MPCVD) technique by varying the concentration of CH4 in the reaction gas and the growth temperature of the diamond composite films. The surface morphology, chemical composition, microstructure, and electron field emission performance of the diamond composite films were analyzed through SEM, XRD, Raman, XPS, AFM, TEM, and electron field emission measurement system. The D/G film deposited at a lower growth temperature (968 ℃) consisted of a nanosheets structure with diamond as the core and graphite as the shell. At a higher growth temperature (1 058 ℃), the plasma energy density was higher, making it easier to form D/CNWs films composed of nanosheets and a three-dimensional network of carbon nanowalls, with the introduction of carbon nanowalls structure resulting in a higher electrical conductivity at the same CH4 concentration. As the CH4 concentration increased, the diamond content in both the D/G film and D/CNWs film decreased, while the graphite content increased. The electrical conductivity of the D/G film increased from 4.98 S/cm to 66.4 S/cm, and the turn-on field decreased from 10.2 V/μm to 7.5 V/μm. Meanwhile, the electrical conductivity of the D/CNWs film increased from 20.5 S/cm to 94.8 S/cm, and the turn-on field also decreased from 8.4 V/μm to 4.0 V μm-1. The increase in the graphite content in the diamond composite films contributed to the increased electrical conductivity of films and the number of emission sites, thereby enhancing the electron field emission performance of the diamond composite films. In addition, for the D/G film deposited at a lower temperature, it was found that the nanocrystalline diamond (NCD) interlayer formed at the film/substrate interface, exhibited a relatively low interfacial electrical conductivity of 12.6 S/cm. In contrast, the D/CNWs film deposited at a higher temperature did not form a NCD interlayer at the film/substrate interface, significantly enhancing the interfacial electrical conductivity which reached as high as 57.8 S/cm. The electron field emission performance of D/CNWs films was significantly superior to that of the D/G film. At a higher CH4 concentration (14%), the D/CNWs film exhibited a turn-on field of 4.0 V/μm and a current density of 3.237 mA/cm2 at an electric field of 7 V/μm. The D/CNWs film without a NCD interlayer prepared by the one-step exhibits higher film electrical conductivity and interfacial electrical conductivity, demonstrating superior electron field emission performance. Therefore, this work paves the way for the construction of electron field emitters based on hybrid sp2/sp3-bonded carbon via one step. |
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