Co掺杂对脉冲激光沉积CdO薄膜结构及性能的影响  

Structure and Properties of CdO Thin Films Prepared by Pulsed Laser Deposition Method with Co Doping

作　　者：江凤仙[1,2,3,4] 纪丽飞 仝瑞雪 Jiang Fengxian;Ji Lifei;Tong Ruixue(School of Chemistry and Materials Science,Shanxi Normal University,Linfen 041004,China;Research Institute of Materials Science,Shanxi Normal University,Linfen 041004,China;Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education,Linfen 041004,China;Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology,Linfen 041004,China)

机构地区：[1]山西师范大学化学与材料科学学院,山西临汾041004 [2]山西师范大学材料科学研究院,山西临汾041004 [3]磁性分子与磁信息材料教育部重点实验室,山西临汾041004 [4]山西先进永磁材料与技术协同创新中心,山西临汾041004

出　　处：《稀有金属》2021年第7期821-827,共7页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2017YFB0405703);山西省自然科学基金项目(201901D111283)资助。

摘　　要：透明导电氧化物是一类在可见光波长范围内具有良好导电特性和光学透明性的材料,由于其在光电器件中的潜在应用而备受人们的关注。在众多的透明导电氧化物中,立方结构的CdO因其具有低的电阻率和在可见光范围内高的透光率而成为人们研究的热点。采用脉冲激光沉积技术在蓝宝石(0001)单晶基片上制备了一系列Co掺杂CdO薄膜。X射线衍射(XRD)结果表明薄膜为均匀的单相立方结构,以CdO(200)和CdO(111)方向择优取向生长,没有发现Co金属及其氧化物二次杂质相。X射线光电子能谱(XPS)测量进一步表明Co以Co^(2+)的形式存在于薄膜中,且处于高自旋电子态。紫外可见光谱测量表明,Co掺杂CdO薄膜在可见光范围内都具有较高的透光率,均在80%以上。改变沉积过程的氧气分压和基片温度可有效调节薄膜的光学带隙,即随着氧气分压和基片温度的升高,薄膜的吸收带边红移,光学带隙逐渐减小,从2.70 eV减小到2.33 eV。磁性测量结果进一步表明,Co掺杂CdO薄膜具有明显的室温铁磁性,且随着氧气分压的升高,薄膜的磁性明显减弱。Co^(2+)提供局域磁矩,薄膜中氧空位提供的额外载流子,有效地调节了Co^(2+)之间的交换作用,从而产生了长程铁磁性。Transparent conducting oxide(TCO)films were materials exhibiting both good conductivity and transparency in the visible-light range,which had attracted much attention due to their potential applications in the optoelectronic devices,such as flat panel displays(FPDs),touch panels,solar cells,and light-emitting diodes(LEDs).CdO,an n-type semiconductor with rock-salt crystal structure had a direct optical band-gap of 2.2 eV.CdO had garnered considerable attentions as TCO materials due to its high electrical conductivity without doping and high transparency in the visible range of solar spectrum with moderate refractive index.Many different deposition techniques,including spray pyrolysis,magnetron sputtering,sol-gel,and chemical vapor deposition,had been used to grow CdO thin film.Among these techniques,the pulsed laser deposition(PLD)method was widely used to grow thin films because of its many advantages,such as good adhesion,accurate stoichiometery,and smooth surface.In the present work,a series of Co doped CdO thin films were deposited on c-plane of Al_(2)O_(3)(0001)substrates by the PLD technique.The structural,optical and magnetic properties of the Co doped CdO thin films were systematically investigated as a function of the oxygen pressure and substrate temperature.X-ray diffraction(XRD)patterns of the Co doped CdO thin films were recorded using theθ-2θscan with Cu Kαradiation(λ=0.15406 nm).Besides the diffraction peaks from the Al_(2)O_(3)substrate,all the diffraction peaks were in good agreement with cubic crystal structure of CdO,and no other impurity peaks were detected.X-ray photoemission spectroscopy(XPS)measurements were further performed to study the composition and chemical states of the thin films.Two peaks at 404.6 and 411.3 eV were attributed to 3d_(5/2)and 3d_(3/2)of Cd^(2+)in CdO,respectively.The peak centered at 529.2 eV was associated to the O^(2-)in the cubic structure CdO,while the peak at531.8 eV could be ascribed to the oxygen defects.The binding energies of Co 2p_(3/2)and 2p_(1/2)were

关 键 词：透明导电氧化物 掺杂 CdO薄膜 脉冲激光沉积 

分 类 号：O484.4[理学—固体物理]