基于电子场发射性能的高导电性金刚石/碳纳米墙薄膜的一步法制备  

One-step Preparation of Diamond/Carbon Nanowalls Films with High Electrical Conductivity Based on Electron Field Emission

作　　者：徐戴 卢嘉琪 刘鲁生[1] 杨越朝 关印 黄楠[1,2] 姜辛 杨兵[1,2] XU Dai;LU Jiaqi;LIU Lusheng;YANG Yuechao;GUAN Yin;HUANG Nan;JIANG Xin;YANG Bing(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《表面技术》2025年第6期194-205,共12页Surface Technology

基　　金：国家自然科学基金(52172056);辽宁省自然科学基金(2022MS009)。

摘　　要：目的 金刚石薄膜的电导率和薄膜/衬底界面电导率的提高对其场发射性能优化非常关键。通过一步法制备具有高导电性且无高电阻率中间层的金刚石/碳纳米墙(D/CNWs)薄膜,提高金刚石的场发射性能。方法 利用微波等离子体化学气相沉积(MPCVD)技术,通过调控生长温度和CH_4浓度,采用一步法制备了2种高导电性的金刚石复合薄膜:金刚石/石墨(D/G)纳米片薄膜和D/CNWs薄膜。采用SEM、XRD、Raman、XPS、AFM、TEM和场发射测试设备对薄膜的形貌结构、化学成分和场发射性能进行分析。结果 在968℃下沉积的D/G薄膜由金刚石为核、石墨为壳的纳米片结构组成。而在较高温度(1058℃)下,形成由纳米片和三维网状的碳纳米墙组成的D/CNWs薄膜,碳纳米墙的引入使其具有更高的电导率。随着CH_4浓度升高,D/G和D/CNWs薄膜中的石墨含量升高,薄膜电导率和发射位点的数量增加,场发射性能提升。此外,D/G薄膜形成了纳米晶金刚石(NCD)中间层,导致界面电导率较低(仅为12.6S/cm)。而无NCD中间层的D/CNWs薄膜,界面电导率高达57.8 S/cm,使其场发射性能显著优于D/G薄膜:在较高CH_4浓度(14%,体积分数)下D/CNWs薄膜的开启场为4.0 V/μm,在7 V/μm电场下的电流密度为3.237 mA/cm^(2)。结论 一步法制备的D/CNWs薄膜具有更高的薄膜电导率和界面电导率,表现出更好的场发射性能。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(1058℃),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 Vμm^(-1).The increase in the graphite content in the diamond composite films contribut

关 键 词：金刚石 石墨 复合薄膜 中间层 场致电子发射 化学气相沉积 

分 类 号：TG174[金属学及工艺—金属表面处理]