ZnO薄膜材料的缺陷和光谱特性

ZnO是一种新型的Ⅱ-Ⅵ族半导体材料,具有许多优异的性能,可望成为新一代光电材料。但ZnO薄膜中存在各种缺陷,它们是制约ZnO发光性能的一个关键因素。本文在查阅文献的基础上,总结了ZnO薄膜材料中可能存在的缺陷和发光谱特性,并就缺陷对发光性能影响的研究现状做了综合评述。     

不同离子掺杂TiO2薄膜及光催化活性研究

采用溶胶-凝胶法分别制备了掺杂Fe^3＋、Cu^2＋、Zn^2＋、Ce^3＋和La^3＋5种不同离子的纳米级TiO2薄膜,使用TiO2薄膜对亚甲基蓝溶液进行光催化试验。研究表明,在5种掺杂离子中,其La^3＋的掺杂效果最好,当La^3＋的适宜含量为1.8%（质量分数）时,掺杂与未掺杂的XRD图谱基本一致;掺入La^3＋离子使得TiO2的晶粒变小,可抑制晶相向金红石相转变;随着焙烧温度的升高TiO2晶粒逐渐变大,温度为700℃时,其粒径为27.6nm,TiO2为混合晶型（锐钛矿型和金红石型）,其活性最高。     

棒状纳米ZnO薄膜晶体管效应的测定

分别采用水热法和微乳法制得了两种直径为10～40nm和60～70nm的棒状纳米ZnO材料;然后将制得的纳米材料乙醇溶液旋涂到石英基片上,将其中一部分旋涂膜进行煅烧,最后将经过煅烧和未经过煅烧的旋涂膜基片采用top-contact的方法镀上电极制成薄膜晶体管进行场效应的测定;实验表明:对于直径不同和同种样品旋涂膜经不同处理的场效应参数存在明显的差异,特别是电子迁移率,直径较大的未经煅烧的纳米ZnO旋涂膜的电子迁移率可以达到μ=156cm2V-1s-1。     

Improvement of optical transmittance and electrical properties for the Si quantum dot-embedded ZnO thin film

A Si quantum dot (QD)-embedded ZnO thin film is successfully fabricated on a p-type Si substrate using a ZnO/Si multilayer structure. Its optical transmittance is largely improved when increasing the annealing temperature, owing to the phase transformation from amorphous to nanocrystalline Si QDs embedded in the ZnO matrix. The sample annealed at 700°C exhibits not only high optical transmittance in the long-wavelength range but also better electrical properties including low resistivity, small turn-on voltage, and high rectification ratio. By using ZnO as the QDs’ matrix, the carrier transport is dominated by the multistep tunneling mechanism, the same as in a n-ZnO/p-Si heterojunction diode, which clearly differs from that using the traditional matrix materials. Hence, the carriers transport mainly in the ZnO matrix, not through the Si QDs. The unusual transport mechanism using ZnO as matrix promises the great potential for optoelectronic devices integrating Si QDs.     

不同退火温度In掺杂ZnO薄膜的表面形貌和光学性质

用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和紫外-可见分光光度计观察4%(原子分数)In掺杂ZnO薄膜的微结构、表面形貌和光学性质.微结构分析表明:薄膜仍为六角纤锌矿结构,由于In杂质的掺入,使得薄膜结晶度劣化,退火温度对薄膜微结构影响较小;表面形貌观察结果显示:薄膜表面凹凸不平,450 ℃退火处理薄膜表面最平坦,尺寸在50～100 nm之间小颗粒致密、均匀地分布于起伏的表面;紫外可见透射谱研究结果表明:随着退火温度升高,薄膜光学带宽E_g由3.267 eV减小到3.197 eV,该结果可能与薄膜表面残余应力发生变化密切相关.     

La+掺杂纳米TiO2薄膜的制备及降解烟雾性能研究

以钛酸丁酯为原料采用溶胶凝胶法制备了金属镧离子掺杂的纳米二氧化钛溶胶通过拉提-浸渍的方法将其负载到载玻片上,并利用X射线衍射(XRD)和扫描电子显微镜(SEM)对薄膜进行表征。研究了镀膜层数,焙烧温度对薄膜的晶型、表面形貌及吸附降解香烟烟雾性能的影响。结果表明,经过500℃热处理后的适量掺杂镧离子的二氧化钛主要以锐钛矿晶型存在,在紫外光照射下对香烟烟雾有很好的吸附降解作用。     

Cu基电沉积ZnO薄膜光催化降解甲基橙研究

以Zn(NO3)2水溶液为电解液,在Cu基体上电沉积ZnO薄膜,用X-射线衍射和扫描电子显微镜对其结构及形貌进行了表征。以甲基橙为目标有机污染物,研究了pH、SO42-和NO3-以及外加阳极偏压对ZnO薄膜光催化性能的影响。实验结果表明,在酸性条件下,可以获得更高的降解率;SO42-的存在明显地抑制了降解过程,而NO3-则有着很大的促进作用;外加阳极偏压在一定程度上改善了光催化降解效果。     

水热法制备In掺杂ZnO薄膜的表面形貌及其光学性质

采用水热法在ZnO籽晶层上制备了不同In掺杂量的ZnO薄膜,用X射线衍射仪(XRD)、原子力显微镜(AFM)、紫外可见分光光度计和荧光光谱仪等测试分析薄膜的微结构、表面形貌、透射谱和室温光致发光谱.结果表明,In离子的掺入未改变薄膜的晶相结构,但抑制了ZnO晶粒的生长,使得ZnO的结晶度明显下降.随着In含量的增加,薄膜表面rms粗糙度和平均颗粒尺寸均逐渐减小,光学带隙Eg先增大后减小.所有薄膜的PL谱中均观察到405 nm左右的紫光发光带,研究了In掺杂量对紫光发光带的强度和峰位的影响,并对其紫光发射机理进行了探讨.     

氧化锌半导体材料的性能研究与制备进展

氧化锌半导体材料以其优良的光电性能在光电子、传感器、透明导体等领域得到广泛应用。综述了氧化锌半导体功能材料在敏感材料、压电材料、导电薄膜等方面的性能、应用及薄膜的制备技术，相对于三维块体材料，氧化锌薄膜可以适应大规模集成电路的需要，更具发展前途和研究价值。氧化锌薄膜的性质随掺杂组分和制备条件的不同而表现出很大的差异性。     

Photoluminescence of ZnO layer on commercial glass substrate prepared by sol–gel process

Amorphous ZnO thin film on soda–lime–silica glass substrate was prepared by the sol–gel process at low-temperature processing, i.e., 100 °C. No distinct grain structure was observable in the surface of the film. The photoluminescence spectrum of the ZnO thin film with an intense near band edge emission was observed while the defect-related broad green emission was nearly quenched.     

化学溶液沉积法制备掺镧Bi2Ti2O7薄膜及其特性的研究

采用化学溶液沉积法,在Si(100)衬底上制备了(Bi0.925La0．075)2Ti2O7薄膜。通过对其X射线衍射图谱分析表明：用一定量的La^3 来代替部分Bi^3 ,提高了Bi2Ti2O7相薄膜的稳定性。研究发现：经过高温(850℃)退火处理后,该薄膜的结晶性和取向性都很好,[111]方向取向率为90X。根据XRD谱图中的(444)衍射峰,计算出晶格常数a≈20．66A。薄膜的电流-电压和电容-电压特性的测量结果表明,该薄膜具有良好的绝缘性和较高的介电常数。     

Optoelectronic performances on different structures of Al‐doped ZnO

ZnO films and Al‐doped ZnO (AZO) films were deposited on p‐Si substrate by magnetron sputtering to investigate its chemical composition, structural and photoelectric properties. XRD and FTIR show that Al ions can enter into the substitutional and interstitial site of ZnO crystal, and O atoms in AZO films are more abundant. Three different structures of Al‐doped ZnO (substitutional Al, interstitial Al, and O‐rich Al‐doped ZnO) were built using first‐principles method based on experimental results, charge density difference, and density of States (DOS) illustrate that there are strong ionic interactions between Al and O atoms in substitutional Al‐doped ZnO, moreover, substitutional and interstitial Al doping both are beneficial to N type, but oxygen‐enriched ZnO is not conducive to N type. Furthermore, the optical properties of 3 different Al‐doped ZnO structures were investigated respectively. Compared with pure ZnO, the real and imaginary part of dielectric function of O‐rich and interstitial Al have a significant increase and move to lower energy (red shift), the reflectivity of O‐rich is 3 times of pure ZnO and substitutional Al‐doped ZnO. The results are hoped to be helpful to study AZO thin film and predict the properties of Al‐doped ZnO.     

The evolution behavior of microstructures and optical properties of ZnO films using a Ti buffer layer

ZnO thin films without and with Ti buffer layer were prepared on Si and glass substrates by radio frequency (RF) magnetron sputtering. The effects of Ti buffer layer with different sputtering time on the microstructure and optical properties of ZnO thin films had been investigated by means of X-ray diffraction (XRD), energy dispersive spectrometer, X-fluorescence spectrophotometer and ultraviolet–visible spectrophotometer. The XRD results showed that the full-width at half-maximum (FWHM) for the ZnO (002) diffraction peak gradually decreased with the increase of sputtering time of Ti buffer layer, indicating that the crystalline quality of ZnO thin films was improved. The UV peak located at 390 nm, two blue peaks located at about 435 and 487 nm, two green peaks located at about 525 and 560 nm were observed from PL spectra. The PL spectra showed that the strongest blue light emission of ZnO films was obtained from Ti buffer layer with the sputtering time of 10 min. Meanwhile, the origins of the emission peaks were discussed through the Gaussian deconvolution. We also studied the optical band gaps.     

Preparation and characterization of ZnO microcantilever for nanoactuation

ABSTRACT: Zinc oxide [ZnO] thin films are deposited using a radiofrequency magnetron sputtering method under room temperature. Its crystalline quality, surface morphology, and composition purity are characterized by X-ray diffraction [XRD], atomic force microscopy [AFM], field-emission scanning electron microscopy [FE-SEM], and energy-dispersive X-ray spectroscopy [EDS]. XRD pattern of the ZnO thin film shows that it has a high c-axis-preferring orientation, which is confirmed by a FE-SEM cross-sectional image of the film. The EDS analysis indicates that only Zn and O elements are contained in the ZnO film. The AFM image shows that the film's surface is very smooth and dense, and the surface roughness is 5.899 nm. The microcantilever (Au/Ti/ZnO/Au/Ti/SiO2/Si) based on the ZnO thin film is fabricated by micromachining techniques. The dynamic characterizations of the cantilever using a laser Doppler vibrometer show that the amplitude of the cantilever tip is linear with the driving voltage, and the amplitude of this microcantilever's tip increased from 2.1 to 13.6 nm when the driving voltage increased from 0.05 to 0.3 Vrms. The calculated transverse piezoelectric constant d31 of the ZnO thin film is -3.27 pC/N. This d31 is high compared with other published results. This ZnO thin film will be used in smart slider in hard disk drives to do nanoactuation in the future.     

SiO_2/ZnO复合薄膜改性及二甲基二氯硅烷修饰的搪瓷表面疏水性能研究

采用水热法,通过反应釜中高温高压在搪瓷表面制备了SiO_2/ZnO复合薄膜。研究了不同反应温度、水热时间与溶胶配比对其疏水性能的影响。利用SEM、红外光谱仪、全自动视频微观接触角测量仪分析了薄膜的微观结构与性能,最后对搪瓷表面进行光泽度、白度、耐酸度的测试。结果表明,反应温度在220℃,水热时间为14 h,SiO_2溶胶与ZnO溶液配比为1∶1时制备的SiO_2/ZnO复合薄膜,经过DDS修饰疏水性能最优,接触角达到150.3°。SiO_2/ZnO复合薄膜对搪瓷的光泽度与白度基本没有影响,不影响表面实际观感,同时搪瓷表面耐酸性为一级。     

溶胶-凝胶旋涂法制备ZnO∶Cd薄膜

溶胶-凝胶法是一种有效制膜技术,以二水合醋酸锌Zn(CH3COO)2·2H2O为前驱体,以乙二醇甲醚CH3OCH2CH2OH为主要溶剂,以乙醇胺C2H7NO作为稳定剂制备溶胶溶液.将滴有此溶胶溶液的基片放入旋转涂覆机旋转,再在表面滴入氯化镉( CdCl2·2.5H2O)溶液,然后对基片进行热处理.经X-射线衍射测量,发...