四方结构GaN纳米线制备、掺杂调控及其场发射性能研究  

Preparation,doping modulation and field emission properties of square-shaped GaN nanowires

作　　者：杨孟骐 姬宇航 梁琦 王长昊 张跃飞[3] 张铭 王波[1] 王如志[1] Yang Meng-Qi;Ji Yu-Hang;Liang Qi;Wang Chang-Hao;Zhang Yue-fei;Zhang Ming;Wang Bo;Wang Ru-Zhi(College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China;School of Physics,Beihang University,Beijing 100191,China;Institute and Beijing Key Laboratory of Solid Microstructure and Properties,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学材料科学与工程学院,新型功能材料教育部重点实验室,北京100124 [2]北京航空航天大学物理学院,北京100191 [3]北京工业大学固体微结构与性能研究,固体微结构与性能北京市重点实验室,北京100124

出　　处：《物理学报》2020年第16期262-270,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11774017,51761135129)资助的课题.

摘　　要：作为最重要的第三代半导体材料之一,纳米氮化镓(Ga N)也引起了人们的广泛关注与重视.本文采用微波等离子体化学气相沉积(microwave plasma chemical vapor deposition, MPCVD)系统,成功地制备出了四方截面的Ga N纳米线,其纳米线半径为300-500 nm,长度为15-20μm.研究发现,通过调控掺杂Mg的比例,可以实现其截面结构从三方向四方转变.通过进一步地研究Mg掺杂调控其截面结构的物理机制,提出其三方-四方截面结构的转变应该来源于其纳米线的气-液-固(VLS)生长向自催化气-固(VS)生长模式的转变.对所制备的纳米线进行了光致发光(photoluminescence, PL)光谱分析,结果表明四方结构Mg掺杂Ga N纳米线发光峰红移至386 nm.采用所制备的纳米线进行了场发射性能研究,结果表明四方结构Mg掺杂Ga N纳米线开启电场为5.2 V/μm,并能保持较高电流密度,相较于三方结构未掺杂Ga N纳米线场发射性能有一定提高,进而分析掺杂以及形貌结构对Ga N纳米线场发射的影响机制.研究结果不仅给出了一种四方结构Ga N纳米线的制备方法,同时也为纳米线结构调控提出了新的思路与方法,将为新型纳米线器件设计与制作提供了新的技术手段.GaN nanomaterials, as one of the most important third-generation semiconductor materials, have attracted wide attention. In this study, GaN nanowires with square cross section were successfully prepared by microwave plasma chemical vapor deposition system. The diameters of nanowires are from 300 to 500 nm and the lengths from 15 to 20 μm. The results show that the cross section of nanowires could be transformed from triangle into square by adjusting the ratio of Mg to Ga in source materials. X-ray diffraction(XRD)result indicate that the structure of GaN nanowires are agree with the hexagonal wurtzite. X-ray photoelectron spectroscopy(XPS)rusult show that a certain amount of Mg and O impurities incoporated in the square-shaped GaN nanowires.Transmission electron microscopy(TEM) result suggested that square-shaped GaN nanowires had high crystallinity with a growth direction of [ 0ˉ110]. The ratio of source materials-and time-depented growth mechanism was also studied. It was suggested that the transformation of the cross section from triangle to square structure should be derived from the growth mechanism change from vapor-liquid-solid(VLS)process to vapor-solid(VS)process. The doped Mg increased the growth rate of the nanowires sidewalls, which led to a symmetrically growth of GaN nanowires along the twin boundaries. GaN nanowires gradually transformed to square structure by auto-catalytic growth. Moreover, the property of field emission were further investigated.The results showed that the turn-on electric field of square-shaped GaN nanowires was 5.2 V/m and a stable field emission property at high electric field. This research provides a new method for the preparation of squareshaped GaN nanowires and a prospective way for the design and fabrication of novel nano-scale devices.

关 键 词：氮化镓(GaN) 四方结构纳米线 Mg 掺杂 场发射 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TN304[电子电信—物理电子学]