阴极电沉积法制备ZnO纳米棒阵列微结构、润湿性等性能的研究

发布时间：2018-03-04 00:17

本文选题：ZnO薄膜　切入点：电沉积　出处：《安徽大学》2017年硕士论文　论文类型：学位论文

【摘要】：ZnO是具有3.37eV能隙的宽带隙半导体,由于其在电子、光子和光学及生物等领域的出色表现,可广泛应用于各类高科技领域。为了制备不同尺寸,晶体结构,晶形和颗粒形状的ZnO,开发了多种制造方法。本文使用阴极电沉积法制备ZnO纳米棒阵列,利用X射线衍射仪、扫描电镜、接触角测量仪、拉曼光谱仪等测试仪器,研究两种基底(ITO/Ti片)上改变沉积时间、电解液组成成分比例对其微观结构形貌、润湿性以及光学性能等的影响。首先,通过改变电化学沉积的时间在ITO基底上制备ZnO纳米棒阵列。XRD结果表明ZnO呈六方纤锌矿结构,随着电沉积时间的增长,结晶度以及002方向的择优取向生长都得到增强,同时纳米棒的直径、表面粗糙度和ZnO纳米棒阵列的厚度都变大。所有的样品都展现出疏水性,水接触角在电沉积120min时逐渐上升到120°,经过10min紫外光照,ZnO纳米棒阵列表面润湿性转化为亲水性,光照后水接触角与未经紫外照射前的比例为73.5%、63.5%、48.3%和24.2%,分别对应沉积时间10min、30min、60min和120min的样品。光致发光(PL)光谱结果显示随着电沉积时间的增加,ZnO的紫外发光峰(本征发光峰)的峰强比由2.26%提升到63.84%,同时可见光发光峰(缺陷导致的发光峰)的峰强比降低,说明沉积时间从10min增长至120min,ZnO薄膜的内在缺陷减少。拉曼图谱的分析表明,ZnO纳米棒阵列在这些条件下呈现439cm-1,566cm-1,和1097cm-1三处特征峰,分别对应了ZnO阵列的E2光声子振动模、EIL光声子振动模以及E3单晶振动模。随后,保持其他条件不变,改变电解液浓度组成(Zn2+浓度不变),在Zn(N03)2中掺入ZnCl2溶液,XRD结果表明,所有的峰都归因于六方纤锌矿结构,晶粒尺寸随着ZnCl2浓度的增加而变小,晶核数量增加,同时c轴(002)方向择优取向减弱。SEM结果显示,随着Zn(NO3)2浓度的降低,纳米结构由棒状变为锥状,其中ZnO的直径,除了浓度比为1:1的样品之外,持续减小,且纳米结构的顶端由"吞并"状态改变为远离,间隙得到增加。PL光谱显示Zn(NO3)2电解液制备的样品A紫外发射峰相对较强,随着电解液中ZnCl2浓度比的增加,紫外发射峰比率增强,纯ZnCl2电解液制备的样品E的紫外发射峰比率为最小,缺陷最多,随着氯离子浓度的增大,一个极少见的位于350nm处的发光峰逐渐显现。在紫外照射之前所有的样品均表现为较强的疏水性,且随着ZnC12浓度的增长,水接触角有先增加后减小的趋势,可能与表面粗糙度变大以及结晶度变差的综合结果有关。ZnO纳米棒阵列的可润湿性在15分钟紫外照射后从疏水性改变为亲水性,并且水接触角的光诱导变化从45 8至12.9%,这可能是与润湿模型的变化、ZnO纳米结构的表面粗糙度大小差异以及间隙有关。紫外吸收谱表明,随电解液中氯离子浓度的增加而增加,禁带宽度不断增加至3.34接近标准值3.37eV。最后,改变沉积时间在Ti片上制备ZnO纳米棒阵列。SEM结果显示,所有样品均为棒状六棱锥形貌,随着电沉积时间的增加,纳米棒的直径、棒之间的间隙减小。在PL光谱中所有样品都具有窄的紫外发射峰,在可见光区显示宽的发光区,并且随着电沉积时间增加,缺陷先减小后增加,在45 min时候达到最小。样品的沉积时间由15分钟增长到60分钟,在紫外照射之前的水接触角逐渐变小,这可能与表面粗糙度变小有关。ZnO纳米棒阵列的可润湿性在2小时紫外照射后全部转换为超亲水性,并且水接触角还原率的光诱导变化先变大后变小,在45 min时达到最大,这可能与润湿模型的转变、ZnO纳米棒阵列的表面粗糙度大小差异以及薄膜的缺陷多少有关。禁带宽度曲线与光电流曲线都与PL光谱有相同的规律性,都在45 min时候达到最大值(紫外峰强、禁带宽度与光电流大小)。
[Abstract]:ZnO is a wide band gap semiconductor 3.37eV gap, because of its excellent performance in electronic, photonic and optical and biological fields, can be widely used in all kinds of high-tech fields. In order to prepare different sizes, crystal structure, morphology and particle shape of ZnO, the development of a variety of manufacturing methods. This paper use cathodic electrodeposition ZnO nanorod array, using X ray diffraction, scanning electron microscopy, contact angle measurements, Raman spectrometer, research on two kinds of substrate (ITO/Ti) on the deposition time, electrolyte composition on the microstructure morphology composition, wettability and optical properties. Firstly, by changing the electrochemical deposition time in the ITO substrate to prepare ZnO nanorod array.XRD results show that ZnO is the six wurtzite structure with the deposition time increases, the crystallinity and the 002 direction of the preferred orientation growth have been enhanced At the same time, the diameter of the nanorods, surface roughness and thickness of ZnO nanorod arrays have become large. All the samples exhibit hydrophobicity, the water contact angle in the electrodeposition of 120min gradually increased to 120 DEG 10min after UV irradiation, ZnO nanorod arrays of surface wetting into hydrophilic, light water contact angle 63.5% and without UV irradiation before the ratio of 73.5%, 48.3% and 24.2% respectively, the corresponding deposition time of 10min, 30min, 60min and 120min samples. The photoluminescence (PL) spectroscopy results show that with the increasing of deposition time, ZnO ultraviolet emission peak (intrinsic emission peak) by the peak intensity ratio 2.26% to 63.84%, while the visible emission peak (peak of defects) that peak intensity ratio decreased, the deposition time increased from 10min to 120min, reduce the internal defects of ZnO thin films. The Raman spectrum analysis showed that ZnO nanorod arrays show 439cm-1 under these conditions 566cm-1, 1097cm-1, and three peaks, corresponding to the E2 optical phonon vibration mode ZnO array, EIL optical phonon vibration mode and vibration mode of E3 single crystal. Then, keeping other conditions unchanged, changes in the composition of the electrolyte concentration (the concentration of Zn2+, Zn in the same) (N03) 2 doped ZnCl2 solution, XRD results show that, all peaks are attributed to six wurtzite structure. The grain size increases with the concentration of ZnCl2 decreases, the nucleation number increased, while the c axis (002) direction orientation weakened.SEM results showed that with Zn (NO3) to reduce the concentration of 2, nano structure by rods is conical. The diameter of ZnO, in addition, the concentration ratio of 1:1 sample decreased continuously, and the top of nano structure by the "annex" state changes from, clearance increased.PL spectra show that Zn (NO3) 2 electrolyte samples prepared by A UV emission peak phase of strong, with the increase of the ratio of ZnCl2 concentration in electrolyte And the UV emission ratio enhanced UV E pure ZnCl2 sample preparation of the electrolyte the emission peak ratio is the smallest, most defects, with the increase of the concentration of chloride ion, a rare peak is located at 350nm gradually. Before UV irradiation all samples showed strong hydrophobicity and with the concentration of ZnC12 increased, the water contact angle is increased first and then decreased, the comprehensive result may be related to surface roughness becomes larger and the poor crystallinity of.ZnO nanorod array wettability in 15 minutes after UV irradiation from hydrophobic to hydrophilic change, and the water contact angle of light induced changes from 458 to 12.9%, this may be the change and wetting model, the surface roughness of ZnO nano structure size difference and gap. The UV absorption spectra showed that increased with the increase of the concentration of chloride ion in the electrolyte, the band gap is increasing To 3.34 close to the standard value of 3.37eV. finally, the deposition time on Ti wafer fabrication of ZnO nanorod array.SEM results showed that all the samples were respectively six pyramid morphology, with the increase of deposition time, the diameter of the nanorods, the gap between the bars decreases. In the PL spectra of all samples have narrow UV emission peaks in the visible region display light emitting region wide, and with the deposition time increased, the defect decreases first and then increases and reaches the minimum at 45 min. When the deposition time of samples from 15 minutes to 60 minutes, the contact angle of growth, gradually decreased before UV irradiation of water, which may be related to the surface roughness is smaller the wettability of the.ZnO nanorod arrays in 2 hours after UV irradiation converted into super hydrophilic and water contact angle reduction rate of light induced changes at first then decreased, reached the maximum at 45 min, this may change with the wetting model The surface roughness of ZnO nanorod arrays is related to the size difference and the defect of the films. The forbidden band width curves and photocurrent curves have the same regularity as those of PL spectra. They reach the maximum value at 45 min (ultraviolet peak intensity, band gap and photocurrent size).

【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.241;TB383.1

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