掺杂ZnO薄膜的研究现状

ZnO薄膜的性质取决于不同的掺杂元素和不同的制备工艺.概述了掺杂ZnO薄膜的研究现状,分析了不同掺杂组分对ZnO薄膜的p型转变特性、发光特性以及铁磁性质的影响,认为稀土掺杂可能使ZnO薄膜产生新的发光特性,共掺杂技术可能是实现ZnO薄膜特性改变的新途径.     

ZnO薄膜发光特性的研究进展

ZnO薄膜具有压电、光电、压敏、气敏、发光等多种特性,应用极为广泛。针对ZnO薄膜的发光特性,对ZnO薄膜的制备、影响其发光特性的因素及其发光机理的研究进展进行了综述。     

ZnO薄膜材料的发光谱

随着人们对ZnO薄膜材料发光特性的不同深入，发现了不同能量位置的多个发光峰，本文对用不同方法制备的ZnO薄膜材料的发光谱、发光特性及其相应的发光机制、国内外研究动态进行了综合评述。介绍了由带间跃迁、激子复合和缺陷能级引起的发光和发光谱特性。     

ZnO/CdO复合薄膜的制备及其性能研究

通过脉冲激光沉积法首次制备了ZnO/CdO复合薄膜。采用X射线衍射、光致发光和电阻率测量分析了薄膜的结构、光学和电学性能。光致发光谱表明所有ZnO/CdO复合薄膜都具有相同的PL发光峰,保持了未掺杂ZnO的发光特性。同时,复合薄膜的电阻率大大地下降了几个数量级,接近了纯CdO薄膜的电阻率。这可以用Matthiessen公式来解释。与传统掺杂方法相比,制备的ZnO/CdO复合薄膜可同时具有ZnO的发光特性和CdO的电学特性,从而获得单一TCO材料所不具备的性能,满足某些特殊需求。     

氧化锌中的本征点缺陷对材料光电性能的影响

ZnO薄膜中的本征点缺陷对材料的电学、发光性能有着至关重要的影响.目前,对本征点缺陷的研究是ZnO领域的一大热点,也是实现ZnO基光电器件的关键技术之一.本文结合最新研究,扼要综述了本征点缺陷的电荷特性、对本征ZnO为n型的作用机理、对p型ZnO制备的影响及点缺陷对薄膜绿光发光的贡献.     

热氧化法制备纳米ZnO薄膜及其发光特性的研究

用热氧化ZnS薄膜方法制备纳米ZnO薄膜．并用X射线衍射谱．光致发光谱表征和研究纳米ZnO薄膜结构特征及热氧化温度对薄膜质量的影响。X射线衍射结果表明纳米ZnO薄膜具有六角纤锌矿结构．且随热氧化温度升高．薄膜晶粒尺寸逐渐增大。光致发光谱是由紫外激子发光和与氧空位有关的深能级缺陷发光组成的．且随热氧化温度升高，激子发光峰发生红移．激子发光和深能级缺陷发光强度之比逐渐增大．在热氧化温度为800℃时，其比值为10。     

丝网印刷纳米ZnO薄膜阴极场致发射的研究

鉴于化学气相沉积生长方法成本高且很难制备出大面积均匀的纳米ZnO薄膜,采用成本低的丝网印刷方法制备了大面积纳米ZnO阴极薄膜.测试研究了分散、热烧结、退火处理对ZnO薄膜的场致发射特性的影响,提出了低成本丝网印刷制备大面积ZnO薄膜阴极热烧结和退火处理的工艺,根据样品的形貌、发射特性和均匀稳定发光的阳极可以判断,最高温度843K的热烧结和823K、10min的退火处理适实用于制作大面积纳米ZnO薄膜场致发射阴极.     

Ni2+掺杂ZnO薄膜及粉体的结构和发光性能研究

采用激光脉冲沉积法,用XeCl准分子激光器在Si (100)基片、真空和5Pa氧气气氛下制备了Ni2+(0.8％(原子分数))掺杂的呈六角纤锌矿结构的ZnO薄膜.氧气气氛下制备的薄膜沿(002)取向生长,表面比较平整,平均颗粒尺寸为80nm.真空条件下制备的薄膜出现Zn2SiO4杂相,平均颗粒尺寸为150nm.和真空条件下制备的薄膜相比,氧气气氛下制备的薄膜具有较强的ZnO本征发光,在425nm附近出现由于填隙Zn缺陷引起的较宽的蓝光发光带,并且在482nm处出现了由于氧空位和氧间隙间的转换引起的较强的蓝光发光峰,同时由于氧缺陷引起的449nm附近的蓝光发光峰强度明显降低.     

硅基Zn2SiO4:ZnO薄膜的电致发光

利用溶胶-凝胶法在重掺硼硅片(p-Si)上制备Zn2SiO4∶ZnO(ZnO嵌入Zn2SiO4基体)薄膜,在此基础上,制备了Zn2SiO4∶ZnO薄膜发光器件。实验表征了Zn2SiO4∶ZnO薄膜的晶体结构和形貌,并研究了该器件的载流子输运和电致发光特性。研究表明:器件表现出一定的整流特性;此外,器件在正向偏压(p-Si接正极)下可以产生来自于ZnO的电致发光,而在反向偏压(p-Si接负极)下几乎不发光。通过对上述器件在正向和反向偏压的能带图进行分析,对其载流子输运和电致发光机理进行了解释。     

ZnO:Zn的光致发光和电致发光性能

在N2 H2还原气氛中以ZnO粉末为原料制备了ZnO:Zn发光膜和粉末.利用X射线衍射、电子扫描显微镜、红外光谱仪、XPS、荧光分光光度计等测试手段表征了样品的结构、形貌、缺陷和发光性能.ZnO:Zn发光膜具有六角纤锌矿晶体结构和良好的c轴取向,结晶性较好,晶粒颗粒均匀.ZnO:Zn发光膜和粉末具有绿色的单谱光致发光和电致发光.发光薄膜的O1s结合能表明,此绿色发光与薄膜内的点缺陷状态密切相关.     

TiO_2过渡层对Si基ZnO薄膜光致发光特性的影响

采用直流反应溅射法在Si(100)衬底上制备了有TiO2过渡层的ZnO薄膜,并与直接在Si上生长的样品进行比较。通过X射线衍射技术和光致发光谱等分别对ZnO薄膜的结构和光学性质进行测量和分析。测量结果表明,引入过渡层后ZnO薄膜的平均晶粒尺寸变大,晶粒间界变少,结晶质量提高,薄膜内的应力得到一定程度的释放。此外,室温光致发光谱表明过渡层使ZnO薄膜的紫外发射明显增强,并研究和分析了其微观机理。     

Al-doped ZnO films by pulsed laser deposition at room temperature

Polycrystalline Al-doped ZnO films with good photoluminescence property were successfully deposited on quartz glass substrates by pulsed laser deposition (PLD) at room temperature. The films were obtained by ablating a metallic target (Zn:Al 3 wt%) at various laser energy densities (1.0-2.1 J/cm²) in oxygen atmosphere (9 Pa). The structure of the films was characterized by XRD. Ultraviolet photoluminescence centered at 359-361 nm was observed in the room temperature PL spectra of the Al-doped ZnO films.     

热处理温度对溶胶-凝胶法制备ZnO薄膜晶体结构和发光特性的影响

采用溶胶-凝胶(Sol-Gel)旋涂法在Si(100)衬底上制备ZnO薄膜,利用X射线衍射(XRD)、光致发光谱(PL)、扫描电子显微镜(SEM)等手段分析制得的ZnO薄膜的晶体结构和发光特性。着重考察了热分解温度对ZnO薄膜晶体结构和发光特性的影响。结果表明,溶胶-凝胶旋涂法制备的ZnO薄膜样品厚度约为220nm,属六方纤锌矿结构,其c轴取向度与热分解温度有很大关系;ZnO薄膜在室温下均有较强的紫外带边发射峰,且紫外带边发射峰与样品c轴取向度没有直接关系,与缺陷有关的可见发射带很弱。     

Optical and photoluminescence studies of gold nanoparticles embedded ZnO thin films

Gold nanoparticles (AuNPs) embedded ZnO thin films were prepared by sandwiching a thin thermally evaporated Au film between two sputtered ZnO films. The films were characterized by high resolution transmission electron microscopy (HRTEM), glancing angle X-ray diffraction (GXRD), optical absorption and photoluminescence (PL) measurements. GXRD data exhibited peaks which were attributed to the reflections from various ZnO and Au planes. Size dependence of the plasmon absorption was studied by forming nanoparticles with various sizes. Optical absorption spectra showed strong absorption due to localized surface plasmons at about 608, 638 and 676 nm for films having average AuNPs sizes of 27, 40 and 67 nm respectively. AuNPs embedded ZnO film showed a strong reduction in the intensity of photoluminescence, which was prominent in the case of pure ZnO film. The rise in temperature at a single nanoparticle site was calculated to be 22 K for a particle size of 80 nm.     

Abnormal photoluminescence of ZnO thin film on ITO glass

The photoluminescence (PL) properties of ZnO thin films on ITO glass substrate deposited by rf magnetron sputtering with different oxygen partial pressures were studied. It was found that the exciton related emission of ZnO thin films depends on oxygen partial pressure, and that the visible emission related to intrinsic defects has no obvious change with various oxygen partial pressures. Abnormal UV-PL characteristics were observed, and its intensity was obviously enhanced. The emission position has a strong red-shift with increasing excitation intensity, and the emission intensity increases notably with increasing excitation cycle.     

低温生长的ZnO单晶薄膜的结构和性能

采用电子束反应蒸镀方法在玻璃衬底上在低温下外延生长了沿 ｃ－轴高度取向的单晶 ＺｎＯ薄 膜,研究了衬底温度及反应气氛中的 Ｏ２对薄膜结构的影响,结合荧光光谱（ＰＬ）和荧光激发光谱（ＰＬＥ） 研究了玻璃上ＺｎＯ薄膜的光学跃迁特性．在３２５℃下获得的单晶薄膜（００２）晶面的ｘ射线衍射峰强度 最大且线宽最窄（０．２８）．反应气氛中的 Ｏ２对 ＺｎＯ 薄膜结构的影响不明显,但对薄膜的 ＰＬ及 ＰＬＥ 特性的影响显著．     

Annealing effects of sapphire substrate on the structure and properties of ZnO films grown via pulsed laser deposition

The structure, morphology, and properties of ZnO films were examined in relation to an annealed sapphire substrate prepared via pulsed laser deposition. The annealing effects of the sapphire substrate on the ZnO films were studied via X-ray diffraction (XRD), atomic-force microscopy (AFM), and photoluminescence (PL) measurements. The XRD patterns and PL spectra results showed that the optical quality of the ZnO films was significantly affected by the annealing temperature of the sapphire substrate. The optimum annealing temperature of the sapphire substrate was 1400 degrees C. Atomically-flat-surface and high-density atomic steps were formed after annealing treatment, which were qualified to be good nucleation sites for ZnO film growth.     

Influence of substrate temperature on ultraviolet emission of ZnO films prepared by ultrasonic spray pyrolysis

ZnO films were deposited on MgO substrates (ZnO/MgO) by ultrasonic spray pyrolysis. Substrate temperature varied from 200 to 350°C. The crystallographic properties and surface morphologies of the ZnO/MgO films were studied by X-ray diffraction and scanning electron microscopy. The properties of photoluminescence (PL) for the films were investigated by dependence of PL spectra on the substrate temperature and the ambient temperature. Ultraviolet (UV) emission peak (3.37 eV) was dominantly detected at 18 K, which sustained at 300 K with a reduced value of the peak energy. The ZnO/MgO films prepared at 350°C showed the strongest UV emission peak at 18 and 300 K among the films in this study.     

Effects of oxygen pressure on the structure and photoluminescence of ZnO thin films

A series of ZnO thin films were deposited on silicon (100) substrate at 473 K by using facing target RF magnetron sputtering system at different oxygen pressure in this paper. The structure, surface morphology and photoluminescence of the ZnO thin films were characterized by X-ray diffraction, atomic force microscopy (AFM), and photoluminescence spectra (PL), respectively. The results showed that only a (002) peak of hexagonal wurtzite appeared in all ZnO thin films, indicating that ZnO films exhibited strong texture. With increasing the oxygen pressure, the results indicated that the ZnO film deposited at 1.2 Pa Ar pressure and 0.6 Pa oxygen pressure had the best preferential C-axis orientation and the weakest compressive stress. Meanwhile, AFM observation showed that ZnO film deposited at pure Ar had the highest surface roughness. With the increment of oxygen pressure, the surface roughness decreased gradually. In addition, PL measurement showed that the ZnO film deposited at 1.2 Pa Ar pressure and 0.6 Pa oxygen pressure had the strongest ultraviolet emission and the weakest blue emission.     

Structural,luminescence and magnetic properties of Mn doped ZnO thin films using spin coating technique

Manganese doped zinc oxide (ZnO) thin films were synthesized for various wt% doping of Mn using sol–gel spin coating technique. The effects of Mn doping on the structural, morphological, compositional, photoluminescence (PL) and magnetic behaviour of ZnO thin films were investigated. Although, Mn doping did not change the lattice constants of the films, the texture coefficient is found to be improved for the films having higher percentage of Mn doping. PL studies reveal that as doping concentration of Mn increases, the intensity of emission peaks corresponding to violet and blue colour increases and the peak position shifts slightly. The saturated magnetic moments are found to decrease with the increase in Mn doping and the reason for such behavior is discussed.