PLD法制备氧化锌薄膜生长机制及发光特性的研究

利用PLD法在Si衬底上成功地制备了具有较好C轴择优取向生长的ZnO薄膜,从样品的XRD谱可以看出在环境氧压为20Pa,衬底温度为700℃时生长的样品的XPD谱(002)峰半高宽较窄,膜的结晶程度最好.不同的衬底温度下膜的生长机制也不一样,主要有:V-L-S机制和V-S机制.样品室温下的PL谱显示所有样品均出现UV发射和可见光区蓝绿光发射,而蓝绿光发射强度随氧压的增大而增强,表明样品的蓝绿光发射来源于样品中的受主缺陷.     

大气开放式MOCVD方法制备ZnO薄膜的气敏特性研究

利用大气开放式MOCVD在氧化铝基片上沉积ZnO薄膜，研究了沉积工艺参数对薄膜形貌的影响，结果表明基片温度对ZnO薄膜的晶体形貌有显著的影响，在一定的条件下能够沉积出具有高比表面积花瓣片层结构的ZnO薄膜。以酒精蒸气为例，研究了ZnO薄膜对碳氢有机化合物气体的气敏特性，结果表明结晶度高且晶粒细小、比表面积高的薄膜具有较好的气敏特性。     

MOCVD制备定向生长ZnO压电薄膜

采用大气开放式金属有机化合物化学气相沉积(A-MOCVD)的方法,在普通多晶黄铜基片上制备ZnO薄膜.薄膜的SEM、XRD结果表明ZnO沿C轴取向垂直生长在基片上.综合分析ZnO自身晶体生长习性,提出了ZnO薄膜在普通多晶铜表面的生长模型.并将ZnO薄膜制备成压电双晶片元件,在光学显微镜下能观察到元件尖端产生了很大的位移量,结果表明高定向性ZnO薄膜具有优异的压电特性.该压电器件使得传统的小变形双晶片元件的数学模型失效,有必要建立新型大变形双晶片物理、数学模型.     

MOCVD方法制备In2O3薄膜的性质研究

用金属有机化学气相淀积（MOCVD）方法以三甲基铟为源材料，以O2为氧化气体，在蓝宝石衬底（0001）面上生长出了高质量的立方相In2O3薄膜。研究了In2O3薄膜的结构、表面形貌和光电性质。结果表明制备样品具有In2O3体心立方结构和（222）方向择优取向生长，电阻率～6．40×10^-3Ω·cm，在可见光区域的平均透过率达到了90％以上。     

MOCVD法制备SnO2单晶薄膜的结构和光学性质

用金属有机物化学气相沉积（MOCVD）法在蓝宝石（0001）衬底上制备出高质量的氧化锡（SnO2）单晶薄膜。对制备薄膜的结构和光学性质进行了研究。制备样品具有纯snO2的四方金红石结构，其外延生长方向为SnO2（100）∥Al2O3（0001）。薄膜均匀、致密，具有很好的取向性和结晶性。透射谱测量结果表明，在可见光区薄膜的绝对透过率达到了90％以上。     

沉积ZnO膜的MOCVD装置的研制

一种新型的MOCVD（Mettalic Organism CVD)装置,既金属有机化合物CVD沉积装置。该装置具有结构简单,在低温、低压条件下能够实现化学气相沉积反应。气路系统全部采用进口零部件,保证反应气体的纯度。等离子体在反应过程中起到辅助和掺杂的作用。经实验表明该装置能够较好地完成氧化锌薄膜的研究工作,也可为进一步的研究提供必要的条件。     

沉积气压对磁控溅射制备ZnO薄膜的结构与光学性能影响

采用CS-400型射频磁控溅射仪在Si(111)和石英基底上成功的制备了ZnO薄膜,分别用XRD、SEM、紫外-可见光分光光度计和荧光分光光度计表征样品的结构和光学性质.实验表明,采用射频磁控溅射制备的ZnO薄膜具有六角纤锌矿结构的(002)峰和(101)峰的两种取向.在沉积气压>1.0Pa时所制备的ZnO薄膜具有(002)择优取向,并且十分稳定.SEM图表明,ZnO薄膜颗粒大小较为均匀,晶粒尺寸随着气压升高而变小,沉积气压不同时,薄膜样品的生长方式有所差异.在400～1000nm范围内,可以看出除O.5Pa下制备的ZnO薄膜外,其余ZnO薄膜在可见光区域的平均透过率超过80%,吸收边在380nm附近,所对应的光学带隙约为3.23～3.27eV,并随着沉积气压上升而变大.ZnO薄膜的PL谱上观察到了392nm的近紫外峰和419nm的蓝峰;沉积气压对Zno薄膜的发光峰位和峰强有影响.     

等离子体辅助MOCVD生长的ZnO薄膜退火改性研究

用等离子体辅助MOCVD法在蓝宝石 (α Al2 O3)上生长了ZnO薄膜 ,测试了其退火和未退火薄膜的电阻率、电子浓度、迁移率、激光阈值 ,并通过X光衍射、光致发光方法表征了ZnO薄膜的质量 ,其结果是 :退火薄膜的电子浓度低达 10 15/cm3 量级、激光阈值降低近 30倍、X光衍射峰半高宽是 0 .2 9°、在 388nm附近的光致发光谱峰半高宽为 0 .32nm。这表明退火使ZnO薄膜的质量得到大幅度提高     

NO和N2O流量对ZnO薄膜p型导电性能的影响

采用金属有机化学气相沉积(MOCVD)方法,由NO和N2O混合气体在玻璃衬底上沉积了p型ZnO薄膜.NO和N2O流量分别为40和25 sccm时,得到最低电阻率5.52Ω·cm,同时样品的空穴浓度最高,为2.17×1018cm-3,电性能的稳定性也最好.全部样品放置四个月后仍为p型,但电阻率增大.     

ZnO薄膜气敏元件

通过在Al2O3衬底上粉末溅射ZnO做出了气敏特性和稳定性较好的ZnO薄膜气敏元件,实现ZnO薄膜的实用化,表明了ZnO是除SnO2外又一种新的气敏基材料.文中还对ZnO薄膜有关气敏特性和元件的气敏电流IG随酒气浓度C变化的规律进行了介绍.     

Effects of sapphire substrates surface treatment on epitaxial ZnO thin films grown by MOCVD

The surface treatment effects of sapphire substrate on the quality of epitaxial ZnO thin films grown by metal-organic chemical vapor deposition (MOCVD) were studied. The sapphire substrates have been investigated by means of atomic force microscopy (AFM) and X-ray diffraction rocking curves (XRCs). The results show that sapphire substrate surfaces have the best-quality by CMP with subsequent chemical etching. The surface treatment effects of sapphire substrate on the ZnO thin films were examined by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. Results show that the intensity of (002) diffraction peak of ZnO thin films on sapphire substrates treated by CMP with subsequent chemical etching is strongest. FWHM of (002) diffraction peak is narrowest and the intensity of UV peak of PL spectrum is strongest, indicating surface treatment on sapphire substrate preparation may improve ZnO thin films crystal quality and photoluminescent property.     

Electrical and optical properties of ZnO:Mn thin films grown by MOCVD

Diluted magnetic semiconductor epitaxial thin films of Zn_1 − xMn_xO have been grown on c-sapphire by the MOCVD technique. Variations of a and c lattice parameters follow Vegard's law and attest to the incorporation of substitutional Mn²⁺ ions. Carrier concentration (n-type) and electron mobility were studied versus temperature for different concentrations of manganese. Incorporation of manganese leads to the opening of the band gap, observed as a blue shift in energy regarding pure ZnO.     

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。     

Effect of oxygen pressure on the structural and optical properties of ZnO thin films on Si (111) by PLD

ZnO thin films were grown on Si (111) substrates by pulsed laser deposition (PLD) at various oxygen pressures in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural and morphological properties of the films were investigated by XRD and AFM measurements, respectively. The results suggest that films grown at 20 Pa and 50 Pa have excellent UV emission and high-quality crystallinity. The research of PL spectra indicates that UV emission is due to excitonic combination, the green band is due to the replacing of Zn in the crystal lattice for O and the blue band is due to the O vacancies.     

Preparation and properties of ZnO thin films deposited by sol-gel technique

Zinc oxide (ZnO) thin films were deposited on (100) Si substrates by sol-gel technique. Zinc acetate was used as the precursor material. The effect of different annealing atmospheres and annealing temperatures on composition, structural and optical properties of ZnO thin films was investigated by using Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy and photoluminescence (PL), respectively. At an annealing temperature of 400°C in N₂ for 2 h, dried gel films were propitious to undergo structural relaxation and grow ZnO grains. ZnO thin film annealed at 400°C in N₂ for 2 h exhibited the optimal structure and PL property, and the grain size and the lattice constants of the film were calculated (41.6 nm, a = 3.253 ? and c = 5.210 ?). Moreover, a green emission around 495 nm was observed in the PL spectra owing to the oxygen vacancies located at the surface of ZnO grains. With increasing annealing temperature, both the amount of the grown ZnO and the specific surface area of the grains decrease, which jointly weaken the green emission. Translated from Journal of Lanzhou University (Natural Science), 2006, 42(1): 67–71 [译自: 兰州大学学报 (自然科学版)]     

Surface and photocatalytic properties of ZnO thin film prepared by sol-gel method

ZnO films were prepared on glass substrates by a sol-gel dip-coating technique. The films showed a polycrystalline phase without any preferable orientation. By decreasing the withdrawal speed, the surface of the ZnO films became denser because of a decrease in particle sizes. This reduces the distance between the supported solids under the water droplet that could increase the degree of the pinning effects, and leads to increase the water contact angle. Furthermore, these prepared ZnO films showed photocatalytic properties indicating by photocatalytic degradation of methylene blue under a blacklight illumination. By increasing the calcination temperature, the water contact angle value decreases due to the grain coalescence which increases the gap between these supported solids. On the other hand, this enhances the photocatalytic activity caused by the improving of the crystallinity and the surface roughness of ZnO thin films with an increase in calcination temperature.     

沉积气压对电弧离子镀制备ZnO薄膜的结构和性能影响

采用阴极真空电弧离子镀技术在玻璃衬底上制备出了具有择优取向的透明ZnO薄膜. 利用X射线衍射仪、扫描电子显微镜及紫外-可见吸收光谱仪分别对ZnO薄膜的结构、表面形貌及可见光透过率进行了分析.XRD结果表明,所制备的ZnO薄膜具有六角纤锌矿结构的(002)和(101)两种取向,在沉积气压＞1.0Pa时所制备的ZnO薄膜具有(002)择优取向,并且非常稳定.SEM图表明,ZnO晶粒大小较为均匀,晶粒尺寸随着气压升高而变小.在400～1000nm范围内,ZnO薄膜的可见光透过率超过80%,吸收边在370nm附近,所对应的光学带隙约为3.33～3.40eV,并随着沉积气压上升而变大.     

多晶纳米ZnO薄膜的溶胶-凝胶法制备及光催化性能研究

在石英玻璃衬底上用溶胶-凝胶法制备了纳米级的多晶ZnO薄膜,通过XRD、AFM和UV-Vis吸收光谱对薄膜进行了表征;以苯酚作为被降解的物质,研究了退火温度、降解温度、苯酚溶液的初始浓度和空气流量对ZnO薄膜光催化降解苯酚性能的影响,以及其光催化活性的失活与恢复.实验结果证明,溶胶-凝胶法制备的纳米级ZnO薄膜光催化效果显著,并且可以再生.     

Influence of annealing on ZnO thin film grown by plasma-assisted MOCVD

ZnO films were grown on C-plane sapphire substrate by plasma-assisted MOCVD. The films was characterized by XRD, photoluminescence (PL) and the optical transmission spectrum. We found tensile strain in the sample, which had been annealed many times during the growth process, while there is compressive strain in the sample, which was annealed only one time after growth. The PL spectra at room temperature for the sample annealed many times exhibited only one emitting peak at around 380 nm. However, we find Γ₅ and Γ₆ free exciton peaks in the sample annealed only one time after growth. At the same time, the optical transmission indicate that the maximum of the sample's transmission decreases against with the increasing of the c-axis length in ranges from 190 to 900 nm.     

退火温度对sol-gel制备的ZnO薄膜的结构影响

采用sol-gel旋涂法在抛光硅〈111〉晶面生长了高度C轴取向的ZnO薄膜。DSC以及XRD测试结果显示此溶胶系统的最佳退火温度为450℃左右,更高的退火温度将对薄膜的择优取向产生不利的影响。SEM显示薄膜表面致密、均匀、光滑,组成薄膜的颗粒尺寸在50～100nm,并显示出良好的C轴择优取向。