全无机ZnO纳米棒/SiO_2电致发光器件的研究  

Study on All-Inorganic Light Emitting Devices Based on ZnO Nanorods with Modification of SiO_2

作　　者：葛林[1] 徐建萍[1] 张晓松[1] 罗程远[1] 王丽师[1] 李梦真[1] 任志瑞[1] 陈义鹏[1] 王有为[1] 石庆良[1] 朱明雪[1] 李岚[1] 

机构地区：[1]天津理工大学材料物理研究所显示材料与光电器件省部共建教育部重点实验室,天津300384

出　　处：《光学学报》2013年第8期217-222,共6页Acta Optica Sinica

基　　金：国家自然科学基金(60977035;10904109;60907021);科技创新体系及条件平台建设计划(10SYSYJC28100)

摘　　要：采用化学溶液法在氧化铟锡(ITO)衬底上合成ZnO纳米棒,以不同的速度将无定形SiO2材料旋涂于ZnO纳米棒,制备了结构为ITO/ZnO/ZnO纳米棒/SiO2/Al全无机电致发光器件。借助能谱(EDS)和吸收光谱,发现当转速从3000r/min降低到500r/min时,SiO2的附着量逐渐增多。比较了旋涂速度对器件的电致发光光谱的影响,发现对于同一旋涂速度形成的器件,紫外发光强度随电压的增大而增强,可见区的发射则逐渐减弱;而不同旋涂速度下获得的器件的紫外发光强度显示出随电压升高先增大后减小的趋势,当旋涂速度为1000r/min时,紫外发射最强,可见区发光几乎消失;I-V曲线测量显示随着转速的降低,器件的启亮电压变大,最大工作电流逐渐变小。结合光致发光(PL)图谱和能级结构图分析认为,SiO2除了能钝化ZnO纳米棒表面缺陷,还具有改善载流子在发光层的平衡和增大电子注入能量的作用,其较高的势垒对发光层内的电子具有限制作用,提高了在活性层中的电子和空穴的复合率。此外,SiO2的加速作用也有助于提高高能态缺陷能级的电子密度及复合几率。ZnO nanorods are synthesised by the chemical solution method on indium tin oxide （ITO） substrate. The all-inorganic light emitting devices, with the structure of ITO/ZnO/ZnO nanorods/SiO2/Al, are obtained with various amount of SiO2 by different spin-coating speeds. According to energy dispersive spectrum （EDS） and absorption spectrum, the modification amount of SiO2 shows a gradual increase when the casting speed is reduced from 3000 r/min to 500 r/min. The electroluminescent （EL） spectra of devices, influenced by the casting speed, are measured and compared. For each spin coating speed, the EL intensity of devices shows obvious enhancement in the ultraviolet （UV） range with the applied voltage increasing ,whick is weakened simultaneously in visible region. The luminescent intensity in UV range enhances obviously when the casting speed increases to 1000 r/min and then declines gradually. At the same time, the visible emission disappears. The I-V curves reveal that the additional SiO2 modification drives up the turn-on voltage of the device monotonically and leads to a decline of maximum operating current. The discussion based on photolumine-scence （PL） spectra and the energy level diagram suggests that, besides surface passivation of ZnO nanorods by SiO2, the high barrier between ZnO and SiO2 induces electron accumulation and suppresses non-radiative recombination at ZnO layer. And the SiO2 on the surface of ZnO nanorods helps to improve the electron density and then the recombination rate at the higher levels of ZnO.

关 键 词：光电子学 ZNO纳米棒 全无机发光二极管 电致发光器件 SiO2表面修饰 

分 类 号：O471.5[理学—半导体物理]