等离子体浸没式氧离子注入技术修饰ITO表面的研究
摘要
有机电致发光器件(OLED)具有自发光、低功耗、响应快、亮度高、可视角度大等特点,是下一代理想的显示技术及面光源.当前OLED广泛采用氧化铟锡(ITO)透明阳极兼出光窗口,然而,ITO表面功函数与器件内层有机材料最高电子占有轨道(HOMO)之间的势垒较高,器件工作电压高,导致能效偏低以及稳定性差等问题.射频等离子体处理ITO可获得一定幅度功函数提高(约0.4eV),但仍未达到与有机材料最高电子占有轨道匹配程度,而且,处理效果时效性很短,只有数小时.而采用等离子体浸没式氧离子注入(PIII)技术修饰ITO表面,可精确控制氧离子注入剂量及深度,改变ITO表层氧、铟、锡3种元素原子比例.在不改变ITO薄膜主体透明性及导电性的基础上,表面功函数提高幅度达0.8eV,与主要的OLED空穴输运有机材料的HOMO能级匹配,并且,处理效果经过50h后未见明显衰退迹象.
引文
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2Wu C C,Wu C I,Strum J C,et al.Surface modification of indium tin oxide by plasma treatment:An effective method to improve the efficiency,brightness,and reliability of organic light emitting devices.Appl Phys Lett,1997,70:1348–1350
3Kim J S,Granstrom M,Friend R H,et al.Indium-tin oxide treatments for single-and double-layer polymeric light-emitting diodes:The relation between the anode physical,chemical,and morphological properties and the device performance.Appl Phys,1998,84:6859–6870
4Mason M G,Hung L S,Tang C W,et al.Characterization of treated indium-tin-oxide surfaces used in electroluminescent devices.Appl Phys,1999,86:1688–1692
5Sugiyama K,Ishii H,Ouchi Y.Dependence of indium-tin-oxide work function on surface cleaning method as studied by ultraviolet and X-ray photoemission spectroscopies.J Appl Phys,2000,87:295–302
6Park Y,Chong V,Gao Y,et al.Work function of indium tin oxide transparent conductor measured by photoelectron spectroscopy.Appl Phys Lett,1996,68:2699–2701
7Milliron D J,Hill I G,Shen C,et al.Surface oxidation activates indium tin oxide for hole injection.J Appl Phys,2000,87:572–576
8Christou V,Etchells M,Renalt O,et al.High resolution x-ray photoemission study of plasma oxidation of indium-tin-oxide films surfaces.J Appl Phys,2000,88:5180–5187
9Yu H Y,Feng X D,Grozea D,et al.Surface electronic structure of plasma-treated indium tin oxides.Appl Phys Lett,2001,78:2595–2597
10You Z Z,Dong J Y,Du F S.Surface modification of indium-tin-oxide anode by oxygen plasma for organic electroluminescent devices.Phys Status Solidi,2004,A201:3221–3227
11Brown T M,Lazzerini G M,Parrot L J,et al.Time dependence and freezing-in of the electrode oxygen plasma-induced work function enhancement in polymer semiconductor heterostructures.Electron,2011,12:623–633
12Lee K H,Jang H W,Kim K,et al.Mechanism for the increase of indium-tin-oxide work function by O2 inductively coupled plasma treatment.J Appl Phys,2004,95:586–590
13Kim J S,Granstrom M,Friend R H,et al.Indium-tin oxide treatments for single-and double-layer polymeric light-emitting diodes:The relation between the anode physical,chemical,and morphological properties and the device performance.J Appl Phys,1998,84:6859–6870
14Milliron D J,Hill I G,Shen C.Surface oxidation activates indium tin oxide for hole injection.J Appl Phys,2000,87:572–576
15Choi B,Yoon H,Lee H H.Surface treatment of indium tin oxide by SF6plasma for organic light-emitting diodes.Appl Phys Lett,2000,76:412–414
16Moulder J F,Strickle W F,Sobl P E,et al.Handbook of X-ray Photoelectron Spectroscopy.Perkin Elmer:Eden Prairie,1992.50
17Fan J C C,Goodenough J B.X-ray photoemission spectroscopy studies of Sn-doped indium-oxide films.J Appl Phys,1977,48:3524–3531
18Ishibashi S,Higuchi Y,Ota Y,et al.Low resistivity indium–tin oxide transparent conductive films.I.Effect of introducing H2O gas or H2 gas during direct current magnetron sputtering.J Vac Sci Technol,1989,A8:1399–1402