直流磁控溅射制备ZnO薄膜的结构及电学性质研究

本文采用直流反应磁控溅射方法在平面玻璃上制备了ZnO薄膜.所得的ZnO薄膜利用X光衍射,扫描电子显微镜和原子力显微镜进行分析和表征.实验结果表明,ZnO薄膜的结构和电学性质与合成条件密切相关.并测试了ZnO薄膜的温差电动势,得出薄膜中的载流子浓度越大,温差电动势率越小;ZnO薄膜厚度越大,温差电动势率越小.本文对其结果进行了理论分析.     

GDARE法制备不同厚度ZnO薄膜的热电性质

以气体放电活化反应蒸发(GDARE)沉积法通过多次沉积制备不同厚度ZnO薄膜。原子力显微镜和X射线衍射测试分析表明,所得ZnO薄膜具有纳米颗粒多晶结构,粒径在30~70 nm,晶粒尺寸随薄膜厚度增加而增大,不同厚度的薄膜均具有高度的c轴取向性。由GDARE法沉积的ZnO薄膜具有较高的温差电动势率S(Seebeck系数),厚度200 nm的薄膜在440K附近S可达600μV/K。相同温度下,薄膜的温差电动势率S与电阻率ρ均随着膜厚的增加而减小。在考察了薄膜电阻率与温差电动势率的综合影响后,得到在440 K附近,厚度为600 nm的ZnO薄膜具有相对最优秀的热电性能。讨论了ZnO薄膜的表面电传导过程及温差电动势产生机制。     

磁控溅射制备银掺杂ZnO薄膜结构及光电性质研究

利用磁控溅射法在玻璃衬底上制备了银掺杂ZnO薄膜,通过改变制备条件生长了一系列样品,样品退火后呈现P型导电特性.测量了样品的结构特性、光学性质和电学性质,实验表明薄膜厚度与淀积时间、溅射功率分别呈近似线性关系;薄膜晶体质量随溅射功率、背景气压的增加而降低;退火过程是银元素形成受主的重要环节,且退火能有效提高薄膜晶体质量,改善薄膜的光学性质和电学性质.分析了这些影响的机理和来源.     

退火处理对N掺杂Al:ZnO薄膜结构及性能的影响

采用射频磁控溅射方法, 常温条件下以N₂作为N掺杂源, 在玻璃基底制备了N掺杂Al:ZnO薄膜。在真空氛围下对样品进行了不同温度的退火处理15 min。通过X射线衍射、霍尔效应测试、紫外-可见光谱和X射线光电子能谱 (XPS) 仪分析了退火对样品结构和光电性能的影响。结果表明真空400℃退火15 min时成功制备出性能优异的p型ZnO薄膜, 其空穴载流子浓度为3.738×10²⁰cm^-3, 电阻率为1.299×10^-2Ω·cm, 样品可见光透射率达到了85%以上。XPS分析说明No受主缺陷的含量大于 (N₂)_o施主缺陷导致薄膜实现了p型转变。     

In掺杂和退火对磁控溅射制备ZnO薄膜的结构和光电性质的影响

用射频磁控溅射技术在石英玻璃衬底上制备出ZnO和In掺杂的ZnO(ZnO∶In)薄膜,研究了In的掺杂和退火对薄膜的结构和光电性质的影响。所制备的薄膜为纤锌矿结构的ZnO相,In的掺杂有利于ZnO薄膜的c轴择优生长,并且使其表面更加致密平整,退火提高了薄膜的结晶行为,但使得薄膜的表面有部分团聚形成。由于In3+替代了Zn2+,提供了一个多余的电子,ZnO薄膜的电阻率从28.9Ω.cm降低到4.3×10-3Ω.cm。由于载流子浓度的增加和晶格尺寸的拉长,In的掺杂使得ZnO薄膜的禁带宽度增加;空气中退火后薄膜的载流子浓度降低和晶格尺寸的减小,使得禁带宽度降低。ZnO薄膜在可见光范围的透光率在90%以上,受In的掺杂和退火的影响不大。室温下用325 nm的激发光源测试了样品的光致发光(PL)谱,发现In的掺杂对薄膜的PL谱影响不大,而退火后的ZnO薄膜在446 nm处的蓝光发射明显增强,更适合于作为蓝色发光器件。     

Al掺杂ZnO薄膜的微结构及光学特性研究

采用射频磁控溅射方法在玻璃衬底上制备出不同Al掺杂量的ZnO(AZO)薄膜。利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致荧光发光(PL)等系统研究了不同Al掺杂量对ZnO薄膜的结晶性能、表面形貌和光学特性等的影响。结果显示,随着Al掺杂量的增加,薄膜的(002)衍射峰先增强后减弱,同时出现了(100)、(101)和(110)衍射峰,表明我们制备的AZO薄膜为多晶纤锌矿结构,适量的Al掺杂可提高ZnO薄膜的结晶质量,然而AZO薄膜的表面平整、晶粒致密均匀。薄膜在紫外-可见光范围的透过率超过90%,同时随着Al掺杂量的增加,薄膜的光学带隙值先增大,后减小。这与采用量子限域模型对薄膜的光学带隙作出相应的理论计算所得结果的变化趋势完全一致。     

Cu基Al掺杂ZnO多层薄膜的生长和性能

本文采用直流磁控溅射技术在玻璃衬底上制备了AZO／Cu、Cu／AZO和AZO／Cu／AZO三种复合结构多层膜,研究了生长温度对多层膜特性的影响,发现AZO／Cu双层薄膜具有最优的光电性能,其最佳生长温度为100～150℃。文中进一步考察了生长温度对AZO／Cu双层薄膜结构性能和表面形貌的影响,结果表明：合适的生长温度有利于改善AZO／Cu双层薄膜的晶体质量,进而提高其光电性能;150℃下沉积的薄膜具有最佳品质因子1．11×10^-2Ω^-1,此时方块电阻为8．99Ω／sq,可见光透过率为80％,近红外反射率约70％。本文在较低温度下制备的AZO／Cu双层膜具有较优的透明导电性和良好的近红外反射     

直流磁控溅射ZnO薄膜的结构和室温PL谱研究

ZnO是一种新型的宽带化合化半导体材料，对短波长的光电 子器件如UV探测器，LED和LD有着巨大的潜在应用。本实验研究采用直流反应磁控溅射法在硅衬底上沉积C轴择优取向的ZnO晶体薄膜，薄膜呈柱状结构，晶粒大小约为100nm，晶粒内为结晶性能完整的单晶，但晶粒在C轴方向存在较大的张应力。ZnO薄膜在He-Cd激光器激发下有较强的紫外荧光发射，应力引起ZnO禁带宽度向长波方向移动，提高衬底温度有利于降低应力和抑制深能级的绿光发射。     

Al-Sn共掺杂ZnO薄膜的结构与光电性能研究

采用射频磁控共溅射法在玻璃衬底上制备出了Al与Sn共掺杂的ZnO(ATZO)薄膜.在固定ZnO∶Al(AZO)靶溅射功率不变的条件下,研究了Sn靶溅射功率对ATZO薄膜的结晶质量、表面形貌、电学和光学性能的影响.结果表明,制备的ATZO薄膜是六角纤锌矿结构的多晶薄膜,具有c轴择优取向,而且表面致密均匀.当Sn溅射功率为5W时,330 nm厚度的ATZO薄膜的电阻率最小为1.49×10-3 Ω·cm,比AZO薄膜下降了22％.ATZO薄膜在400～900 nm波段的平均透过率为88.92％,禁带宽度约为3.62 eV.     

Ga-Ti共掺杂ZnO透明导电薄膜的微观结构和光电性能研究

采用磁控溅射方法在玻璃基片上制备了Ga-Ti共掺杂ZnO(GTZO)透明导电薄膜,通过XRD、四探针仪和分光光度计测试,研究了氩气压强对GTZO薄膜光电性能和晶体结构的影响。结果表明:所有GTZO薄膜均为(002)择优取向的六角纤锌矿结构,其光电性能和晶体结构与氩气压强密切相关。当氩气压强为0.4Pa时,GTZO薄膜具有最大的晶粒尺寸(85.7nm)、最小的压应力(-0.231GPa)、最高的可见光区平均透射率(86.1%)、最低的电阻率(1.56×10-3Ω·cm)和最大的品质因子(4.28×105Ω-1·cm-1),其光电综合性能最佳。另外,采用光学表征方法计算了薄膜的光学能隙和折射率,并利用有效单振子理论对折射率的色散性质进行了分析,获得了GTZO薄膜的色散参数。     

Optical and photoluminescent properties of sol-gel Al-doped ZnO thin films

Al-doped zinc oxide (AZO) thin films have been prepared via a sol-gel process. Optical and photoluminescent properties of the AZO films have been investigated. The UV absorption edge was blue shifted with increasing Al doping concentration. Efficient green–yellow emission was obtained after annealing at 850 °C. For the 850 °C-annealed samples, the green peak was red shifted from 518 to 565 nm as the Al doping concentration increased from 0 to 2.0 at.%. In addition, violet emission in the range of 400–450 nm was observed in the 850 °C-annealed AZO films. The possible origins responsible for these emission bands have been discussed.     

Microstructure and gas-sensing properties of sol-gel ZnO thin films

The paper presents the properties of zinc oxide thin films deposited on glass substrate via dip-coating technique. Zinc acetate dehydrate, ethanol and monoethanol amine were used as starting materials and N₂ gas was used as thermal annealing atmosphere for film crystallization. The effect of withdrawal speed on the crystalline structure, morphology, zinc and nitrogen chemical states, optical, electrical and gas-sensing properties of the thin films has been investigated using X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, optical transmittance and photoreduction-ozone reoxidation data.     

金属铝离子注入掺杂制备氧化锌铝薄膜的研究

本文采用中频孪生非平衡磁控溅射设备制备非晶ZnO薄膜,再以不同剂量的铝离子注入法制备氧化锌铝薄膜.并采用X射线、扫描电镜、四极电阻仪、霍尔效应等方法测量和分析了原始沉积的和铝金属离子注入掺杂ZAO膜在不同温度下退火的组织结构、形貌、电阻与工艺的关系.结果表明,金属离子注入铝的方法制备氧化锌铝薄膜的电阻值随着注入剂量的增加而减小,呈线形关系,透明度均在90%左右,在铝离子注入剂量大于1×1016时,透光率在75%～80%.研究表明,该方法可以任意调整铝离子的注入剂量,获得要求特性的ZAO薄膜.     

Influence of Al concentration on structural and optical properties of Al-doped ZnO thin films

Undoped ZnO and Al-doped zinc oxide (ZnO:Al) thin films with different Al concentrations were prepared onto Si (100) substrate by pulsed filtered cathodic vacuum arc deposition system at room temperature. The influence of doping on the structural and optical properties of thin films was investigated. The preferential (002) orientation was weakened by high aluminum doping in films. Raman measurement was performed for the doping effects in the ZnO. Atomic force microscopy images revealed that the surface of undoped ZnO film grown at RT was smoother than that of the Al-doped ZnO (ZnO:Al) films. The reflectance of all films was studied as a function of wavelength using UV–Vis–NIR spectrophotometer. Average total reflectance values of about 35 % in the wavelength range of 400–800 nm were obtained. Optical band gap of the films was determined using the reflectance spectra by means of Kubelka–Munk formula. From optical properties, the band gap energy was estimated for all films.     

Preparation of highly transparent conductive Al-doped ZnO thin films and annealing effects on properties

Aluminum-doped ZnO (ZAO) thin films were deposited on fused quartz substrates by radio frequency sputtering in pure argon ambient at 450 °C. Effects of in situ annealing temperature and annealing atmosphere on microstructure, electrical and optical properties of ZAO films have been investigated. Results showed that as-grown film without annealing treatments attained lowest resistivity of 1.1 × 10⁻⁴Ω cm. And all films performed high average transmittance greater than 90% in visible region. X-Ray diffraction (XRD), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS) were utilized to characterize the microstructure properties of films. XRD results indicated that as-grown film had higher crystalline quality and larger grain size than annealed films. Al atoms replaced Zn efficiently to provide electrons stable in all samples. PL spectra revealed that high annealing temperature and oxygen atmosphere would generate more Zn vacancy (V_Zn) and oxide antisite defect (O_Zn), respectively and composition content results from XPS provided supports to this.     

Microstructure and properties of Al-doped ZnO thin films by nonreactive DC magnetron sputtering at room temperature following rapid thermal annealing

A series of Al-doped ZnO (AZO) thin films deposited by nonreactive DC magnetron sputtering at room temperature following rapid thermal annealing was studied to examine the influence of these Al doping concentration, sputtering power and annealing temperature on their microstructure, electrical and optical transport properties. AZO thin films with Al dopant of 3 wt% were oriented more preferentially along the (002) direction, bigger grain size and lower electrical resistivity The resistivity of AZO films decreases with the increase of Al content from 1 to 3 wt%, sputtering power from 60 to 100 W and the annealing temperature from 50 to 250 °C. Sputtering power and annealing had some effect on the average transmittance of AZO thin films. For AZO thin films with Al doping level of 3 wt%, the lowest electrical resistivity of 5.3 × 10⁻⁴ Ω cm and the highest optical transmittance of 88.7% could gain when the sputtering power was 100 W and the annealing temperature was 200 °C or above.     

铝掺杂氧化锌薄膜的光学性能研究

采用溶胶-凝胶法,在玻璃基底上制备了掺杂不同质量分数Al的ZnO薄膜,并采用X射线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外-可见光谱仪(UV-Vis)、光致发光光谱(PL)等方法测试和分析了不同Al掺杂浓度对ZnO薄膜的形貌结构、光学性能影响。结果表明,Al的掺杂引起了晶体生长过程中择优取向的改变,掺杂ZnO薄膜的表面颗粒随Al掺杂量的增加而增大,可见光范围内的平均透射率78%,光致发光光谱分析表明,纯的ZnO薄膜有很强的紫外发光,而随Al的质量分数的增加,紫外发光强度迅速下降。     

Structures and properties of the Al-doped ZnO thin films prepared by radio frequency magnetron sputtering

Al-doped ZnO thin films were deposited by radio frequency magnetron sputtering using a ZnO target with 2 wt.% Al₂O₃. The structures and properties of the films were characterized by the thin film X-ray diffraction, high resolution transmission electron microscopy, Hall system and ultraviolet/visible/near-infrared spectrophotometer. The Al-doped ZnO film with high crystalline quality and good properties was obtained at the sputtering power of 100 W, working pressure of 0.3 Pa and substrate temperature of 250 °C. The results of further structure analysis show that the interplanar spacings d are enlarged in other directions besides the direction perpendicular to the substrate. Apart from the film stress, the doping concentration and the doping site of Al play an important role in the variation of lattice parameters. When the doping concentration of Al is more than 1.5 wt.%, part of Al atoms are incorporated in the interstitial site, which leads to the increase of lattice parameters. This viewpoint is also proved by the first principle calculations.     

Effect of Al concentrations on the electrodeposition and properties of transparent Al-doped ZnO thin films

Al-doped zinc oxide (AZO) thin films are prepared on polycrystalline fluorine-doped tin oxide-coated conducting glass substrates from nitrates baths by the electrodeposition process at 70 °C. The electrochemical, morphological, structural and optical properties of the AZO thin films were investigated in terms of different Al concentration in the starting solution. It was found that the carrier density of AZO thin films varied between ?3.11 and ?5.56 × 10²⁰ cm^?3 when the Al concentration was between 0 and 5 at.%. Atomic force microscopy images reveal that the concentration of Al has a very significant influence on the surface morphology and roughness of thin AZO. X-ray diffraction spectra demonstrate preferential (002) crystallographic orientation having c-axis perpendicular to the surface of the substrate and average crystallites size of the films was about 33–54 nm. With increasing Al doping, AZO films have a strong improved crystalline quality. As compared to pure ZnO, Al-doped ZnO exhibited lower crystallinity and there is a shift in the (002) diffraction peak to higher angles. Due to the doping of Al of any concentration, the films were found to be showing >80 % transparency. As Al concentration increased the optical band gap was also found to be increase from 3.22 to 3.47 eV. The room-temperature photoluminescence spectra indicated that the introduction of Al can improve the intensity of ultraviolet (UV) emission, thus suggesting its greater prospects in UV optoelectronic devices. A detailed comparison and apprehension of electrochemical, optical and structural properties of ZnO and ZnO:Al thin films is done for the determination of optimum concentration of Al doping.     

Microstructure and thermoelectric properties of p-type Bi-Sb-Te-Se thin films prepared by electrodeposition method

P-type Bi-Sb-Te-Se thermoelectric thin films with thickness of 8 μm have been prepared by cathodic electrodeposition technique on Au substrate from nitric acid solution system at room temperature. Cyclic voltammetry was used for determination of the deposition potentials of the thin films. In order to enhance the crystallinity, as well as the thermoelectric properties of the deposited films, they were annealed at 523 K for 2 h under nitrogen atmospheric pressure condition. X-ray diffraction (XRD), environmental scanning electron microscopy, and energy-dispersive spectroscopy (EDS) were employed to characterize the thin films. Seebeck coefficients and resistivities of the films were also evaluated. The results revealed that Bi, Sb, Te and Se could be co-deposited to form Bi-Sb-Te-Se semiconductor compound in the solution containing Bi^III, Sb^III, Te^IV and Se^IV and the compositions of the films were sensitive to the electrodepositing potentials. The XRD results suggested that the crystal structure of the thin films were changed from amorphous state to polycrystalline after annealing. The EDS data indicated that the composition of the films was consistent with XRD results. The annealed Bi-Sb-Te-Se thin films exhibited the Seebeck coefficients of 116-133 μV/K and a maximum power factor of 0.62 mW·K^− 2·m^− 1.