溶胶-凝胶法制备ZnO及Fe掺杂ZnO薄膜及其表征

采用溶胶-凝胶法在玻璃基体上制备了ZnO和Fe掺杂ZnO薄膜,并通过扫描电子显微镜、原子力显微镜、X射线衍射仪和紫外-可见分光光度计对所制备薄膜的表面形貌、结构和光学性能进行分析。结果表明,2种薄膜均表面光滑,为沿(101)晶面取向的纤锌矿结构;与ZnO薄膜相比,Fe掺杂ZnO薄膜表面更光滑,且晶粒尺寸从58.512nm减小到36.460nm;另外,Fe掺杂后,沿(101)晶面的取向程度减弱,且禁带宽度由3.1eV增大到3.4eV。     

Mg掺杂ZnO薄膜的结构和光学性质

采用磁控溅射方法在硅和石英衬底上制备了纯ZnO和Mg0.04Zn0.96O薄膜.用XRD和AFM表征薄膜的晶化行为和显微结构,用透射谱和光致发光谱分析薄膜的光学性质.分析结果显示:两种薄膜均为六角纤锌矿结构,且沿c轴取向,薄膜表面光滑致密,晶粒分布均匀;薄膜在可见光范围内具有较高的透过率,Mg掺杂后透射谱吸收边向高能侧移动,相应的薄膜的带隙宽度从3.28 eV升至3.36 eV;用包络法计算出薄膜的光学常数表明,Mg掺杂没有明显改变薄膜的折射率,但使消光系数明显增大;薄膜的光致发光谱分析也发现,掺入Mg使带边发射峰蓝移.     

Structure,optical, and magnetic properties of Mn-doped ZnO films prepared by sputtering

The microstructural, optical, and magnetic properties and room-temperature photoluminescence (PL) of Mn-doped ZnO thin films were studied. The chemical compositions were examined by energy dispersive X-ray spectroscopy (EDS) and the charge state of Mn ions in the ZnO:Mn films was characterized by X-ray photoelectronic spectrometry (XPS). From the X-ray diffraction (XRD) data of the samples, it can be found that Mn doping does not change the orientation of ZnO thin films. All the films prepared have a wurtzite structure and grow mainly along the c-axis orientation. The grain size and the residual stress were calculated from the XRD results. The optical transmittance of the film decreases with the increase of manganese content in ZnO. The room-temperature photoluminescence of the films shows that the intensity of near band energy (NBE) emission depends strongly on the Mn content. The hysteresis behavior indicates that the films with the Mn content below 9at% are ferromagnetic at room temperature.     

Co掺杂ZnO薄膜的结构及光磁性能研究

采用溶胶-凝胶旋涂法在玻璃衬底上制备了Zn1-xCoxO(x=0,0.01,0.03,0.05,0.08,0.12)薄膜.利用显微镜和X射线衍射(XRD)研究了ZnO:Co薄膜的表面形貌和微结构.结果表明,所有ZnO薄膜样品都存在(002)择优取向,尤其是当掺杂浓度为12%时,薄膜c轴择优取向最为显著.振动样品磁强计(VSM)测量表明Zn1-xCoxO薄膜具有室温铁磁性.室温光致发光测量发现,所有样品的PL谱中都出现了较强的蓝光双峰发射和较弱的绿光发射,分析认为这主要是由于Co元素的掺入改变了薄膜的禁带宽度、锌填隙缺陷和氧位错缺陷浓度,其中长波长的蓝光峰和绿光峰都能够通过掺杂进行控制.基于上面的测量结果,探讨了不同波段光发射的机理与掺杂状态之间的关系.     

生长条件对TiO_2薄膜结构及光学性能的影响

为了研究TiO2薄膜的生长机制及结构对其带隙的影响,采用激光脉冲沉积方法在超高真空下制备了TiO2薄膜.X射线衍射结果显示在不同温度和不同缓冲层上生长的TiO2薄膜以板钛矿结构为主,缓冲层对薄膜结构影响不大,高的生长温度提高了薄膜的结晶度.透射谱的结果表明,随着生长温度和生长气压的升高,TiO2的带隙逐渐增大,在生长ZnO做为缓冲层后,TiO2薄膜的结晶度降低,随ZnO结晶度的提高,TiO2对复合薄膜带隙的影响消失.     

磁控溅射制备参数对 ZnO:Al电学性能的影响

ZnO:Al(ZAO)透明导电薄膜是一种n型半导体,有高的载离子浓度和大的光学禁带宽度,具有优异的电学和光学性能,有极广的应用前景.本文介绍了ZAO薄膜的广泛用途和今后研究的趋势,并着重分析了磁控溅射制备参数对电学性能的影响.     

掺杂与应力对ZrO2薄膜电子结构和光学性质的影响

利用基于密度泛函理论的第一性原理平面波超软赝势方法系统地研究了掺杂和应力对ZrO_2薄膜的电子结构与光学性质的影响.本文首先研究了Hf原子替代掺杂对ZrO_2薄膜物性的影响,研究结果表明,Hf原子掺杂减小了ZrO_2薄膜的带隙和态密度大小,可在一定程度上降低其表面缺陷电荷和漏电流.掺杂Hf原子后介电峰和吸收峰的值明显下降,同时介电峰和吸收峰的波形均出现了窄化现象,半高宽显著减小.本文也着重研究了不同应力下四方晶相ZrO_2薄膜物理性质变化及规律.研究发现压应力显著调控了ZrO_2薄膜的带隙以及价带顶和导带底附近的能带结构.施加应力后吸收峰的吸收范围和强度均显著增大,峰值对应的光子能量蓝移则表明对紫外光的吸收随着应力的增加有所增强.在低能量红外和可见光区域,施加压应力后ZrO_2薄膜的折射率变大,但在紫外线区域,压应力使ZrO_2薄膜的折射率呈现出先增大后减小的波动特性.上述研究结果为ZrO_2薄膜材料的设计与应用提供了理论依据.     

溅射气氛对ZnO∶N薄膜光学性能的影响

以ZnO陶瓷为靶材,高纯N_2和Ar为溅射气体,利用磁控溅射生长系统制备N掺杂ZnO薄膜.通过改变溅射气氛中N_2的流量,研究ZnO薄膜光学性能的变化规律,其中N_2流量分别控制为0,8,20,32mL/min.结果表明:当溅射气氛中N_2流量增加时,ZnO∶N薄膜的光学带隙发生改变,吸收边红移;在室温光致发光光谱中,紫外激子发射峰与可见光区发射峰强度的比值变小,紫外激子发射峰位红移;在Raman光谱中,位于272,642cm-1附近的振动模增强.     

GaN/ZnO固溶体电子结构与光学性质的第一性原理研究

GaN/ZnO固溶体具有良好的光催化活性。为研究不同ZnO物质的量对GaN/ZnO固溶体能带结构和光吸收性能的影响,构建了一系列GaN/ZnO固溶体的随机原子结构模型。基于密度泛函理论计算不同ZnO物质的量对GaN/ZnO固溶体模型电子结构和光学性质的影响。研究结果表明： ZnO/GaN固溶体形成能与结合能均为负值,结构稳定。随着ZnO物质的量的增加,固溶体的带隙先呈现下降趋势,最后呈现小幅上升趋势。对于ZnO物质的量分数在13.89%至22.22%的GaN/ZnO固溶体,可以观察到光吸收峰强度在可见光区各个波长范围内均有较强吸收。通过研究不同ZnO物质的量对GaN/ZnO固溶体能带结构和光吸收性能的影响,为GaN/ZnO固溶体光催化材料的设计与制备提供了理论参考。     

Influence of Al doping on the crystal structure,optical properties,and photodetecting performance of ZnO film

The structural,optical,and electrical properties of undoped and Al-doped ZnO films deposited on p-Si(001)substrate were studied using DC-unbalanced magnetron sputtering.This study is motivated by the absence of detail reports concerning the orbital states inducing the optical bandgap(E_g) blueshift.Besides,the influences of Al on the possible modification of point defect and the photodetecting performance are highlighted to offer guidelines for better development in ZnO-based photodetector.It was found that the Al doping reduced the grain size.The doping increased the lattice parameters and slightly decreased the local-symmetry distortion at ZnO_4.From the absorbance spectra,the doping increased Eg of ZnO film(3.28-3.36 eV),induced by the Burstein-Moss effect.From the density-functional calculation,the Burstein-Moss effect induced E_g from the valence band maximum(VBM) to Fermi level located above the lowest Zn 4s conduction state.From the photoluminescence spectra,the undoped film showed the transitions from O vacancy,Zn interstitial,and free-exciton states to the VBM.The doped film showed the transitions from Zn interstitial to O interstitial and few Zn vacancy states at the cost of O vacancies.Moreover,the energy level of free-exciton states slightly decreased.Notably,O interstitials increased the lattice parameters.From the electrical properties,the doping enhanced the ultraviolet-region photo-to-dark-current ratio up to 3.044 V,leading to the photodetecting sensitivity enhancement.This study emphasizes the significant effect of Al doping on the optical absorbance,point-defect evolution,and photodetecting performance of ZnO film for low-voltage ultraviolet photodetector applications.     

Cu-Cd共掺杂ZnO电子结构与光学性质的第一性原理计算与分析

基于密度泛函理论系统下的第一性原理,对纯ZnO,Cd掺杂ZnO,Cu掺杂ZnO,Cu-Cd共掺杂以及Cu-2Cd共掺杂ZnO五个超晶胞模型分别进行几何结构优化;计算和分析了各体系的晶胞结构,能带结构,态密度以及光学性质方面的介电函数虚部,吸收率和反射率.研究结果表明:Cu,Cd单掺杂可提高ZnO的载流子浓度,改善ZnO的导电性;但Cu和Cd共掺杂ZnO时,体系的E更低,状态更加稳定.光学性质方面:Cd掺杂时,紫外区边发生红移,吸收系数略增大;当Cu单掺以及Cu和Cd共掺杂ZnO,体系在可见光和紫外波段吸收系数明显增大,使得ZnO光催化性能提升;结合Cu和Cd单掺杂的特性,说明当Cu和Cd共掺杂ZnO时,控制Cd的掺杂浓度,半导体会产生不同的透光率,因此控制Cu-Cd的比率来掺杂ZnO可用于制作不同效率的光透性器件.     

Co掺杂对Zn1-xCoxO稀磁半导体光学性质的影响

溶胶-凝胶法制备了Co掺杂的ZnO基稀磁半导体,研究其粉体和薄膜的结构和光学特性.X射线衍射结果表明Co2 随机替代Zn2 位置进入ZnO晶格,并引起晶格常数的变化.紫外-可见透射光谱表明样品的禁带宽度随着Co掺杂浓度的增大呈现非单调变化规律,低浓度掺杂样品的光学带隙随掺杂浓度增大而减小(红移),这是由于Co2 替代Zn2 ,局域d电子与能带电子之间的sp-d交换耦合引起的.     

Structural and optical properties of Zn1−xNixTe thin films prepared by electron beam evaporation technique

Zn1-xNixTe thin films with different composition(x=0.0, 0.05, 0.10, 0.15 and 0.20) were deposited on glass substrate by electron beam evaporation technique followed by its characterization using advanced structural and optical analysis techniques. Structural properties of the prepared thin films were studied by X-ray diffraction(XRD). The XRD patterns revealed that the binary compounds transformed into a ternary compound with cubic structure having preferred orientation along the c-direction with(111) planes. Composition analysis of the films was determined by energy dispersive analysis of X-rays(EDAX) and found to be in agreement with the precursor composition. Optical properties such as extinction coefficient(k) and band gap energy of these films were examined by using a spectroscopic ellipsometer. It was found that the extinction coefficient(k) increased with the addition of Ni content in the alloy. In comparison, the band gap energy was also determined by using transmission spectra and found to be agreed with that of the ellipsometric results. These analyses confirm that the band gap energy decreases with the increase of Ni content in the alloy.     

用椭圆偏振光谱法研究取代基对酞菁薄膜光学常数的影响

利用M-2000UI型宽光谱可变入射角椭偏仪研究十六氟铜酞菁(F16CuPc)和铜酞菁(CuPc)薄膜的光学性质. 在248～1 650 nm使用逐点拟合的方法对测得椭偏光谱进行分析, 获得两种薄膜的折射率、消光系数、复介电常数和吸收系数. 讨论了外环氟取代基对酞菁光学性质的影响, 结果表明, 共轭酞菁大环上的外围取代基对薄膜的响应波长和非正常色散影响较大. 分析了两种酞菁的电子结构及吸收谱成因, 并由吸收边外推得到两种材料的光学禁带宽度(Eg).     

ZnO薄膜的制备和研究进展

ZnO作为一种新型的宽禁带半导体材料，具有很好的化学稳定性和热稳定性，抗辐射损伤能力强，在光电器件、压电器件、表面声波器件等诸多领域有着很好的应用潜力．本文介绍了ZnO薄膜的基本性质以及喷雾热分解、脉冲激光沉积、金属有机物化学气相沉积等制备ZnO薄膜的技术和方法，并着重介绍了在ZnO紫外受激发射和p型掺杂等方面的研究进展．     

磁控共溅射法制备Zn_(1-x)Cr_xO薄膜及其结构性能

本文采用磁控共溅射方法在玻璃衬底上制备了Cr掺杂ZnO薄膜,通过改变Cr溅射功率,从而改变Cr的掺杂量.介绍了Zn1-xCrxO薄膜的制备方法,分别用X射线衍射(XRD)和X射线光电子能谱(XPS)对不同Cr溅射功率的一系列薄膜的结构,成份、元素含量及价态等性能进行了分析.结果表明,Cr溅射功率为20 W的样品,具有最好的c轴择优取向,Cr以+3价形式掺入薄膜中,Cr3+替代了部分Zn2+.     

铝掺杂氧化锌薄膜的光学性能及其微结构研究

以氧化铝(Al2O3)掺杂的氧化锌(Zn O)陶瓷靶作为溅射靶材,采用射频磁控溅射工艺在玻璃基片上制备了具有c轴择优取向的铝掺杂氧化锌(Zn O:Al)薄膜样品.通过可见-紫外光分光光度计和X射线衍射仪的测试表征,研究了生长温度对薄膜光学性能及其微结构的影响.实验结果表明:薄膜性能和微观结构与生长温度密切相关.随着生长温度的升高,样品的可见光平均透过率、(002)择优取向程度和晶粒尺寸均呈非单调变化,生长温度为640 K的样品具有最好的透光性能和晶体质量.同时薄膜样品的折射率均表现为正常色散特性,其光学能隙随生长温度升高而单调增大.与未掺杂Zn O块材的能隙相比,所有Zn O:Al薄膜样品的直接光学能隙均变宽.     

Tunability of physical properties of (Cd:Zn)S thin film by Close Space Sublimation Process (CSSP)

The present paper reports on a systematic study of the influence of Zn alloying on the structural and optical properties of Cd1 xZnxS thin films. X-ray diffraction study for structural analysis reveals that the two binary compounds have been completely transformed into ternary compound with hexagonal (wurtzite) structure with preferred orientation along c-direction with (002) planes. The optical properties such as optical constants and band gap energy of the films were examined by using spectroscopic ellipsometer and Photospectrometery. It was found that the optical constants (n and k) decrease with the addition of Zn content in the alloy. It was also confirmed that the band gap increases with increasing Zn amount in the alloy and is attributed to quantum size effect in the grain size. Raman spectroscopy analysis shows one dominant phonon band at 326 cm 1, the so-called longitudinal optical (LO) mode for all the alloy composition (x). The appearance of a single phonon band in the Raman spectra established the formation of single phase hexagonal structured Cd1 xZnxS thin film. The LO band is asymmetrically broaden and high frequency shifted due to potential fluctuation caused by the dopant material. The AFM results showed that the surface roughness was decreased with increasing Zn content.     

Influence of laser doping on nanocrystalline ZnO thin films gas sensors

The effect of laser doping of Al on the gas sensing behavior of nanocrystalline ZnO thin films is reported. The doping of Al was carried out by the spin-coating of Al-precursors on nanocrystalline ZnO films followed by a pulsed laser irradiation. The laser-doped films were characterized as a function of laser power density by measuring the optical, structural, electrical, morphological and gas sensing properties of ZnO films. It was found that the laser doping process resulted in an increase of electrical conductivity of ZnO films. The performance of gas sensor was investigated for different concentrations of H2 and NH3 in the air. The results indicate that the laser doping process can be utilized to improve the sensor characteristics such as sensitivity and response time by optimization of laser power density. The optimum laser power is interpreted as the critical power level required to compete the effective doping versus developing the effective grain boundaries. Also, the selectivity of laser-doped ZnO sensors for H2 was studied for a likelihood practical gas mixture composed of H2, NH3 and CH4. It is found that these films can be optimized to develop H2 and NH3 sensors in PPM level with a higher selectivity over other reducing gases.     

衬底温度和溅射功率对AZO薄膜性能的影响

采用RF磁控溅射法在载玻片上制备了可用于电极材料的掺Al氧化锌(AZO)透明导电薄膜,并对不同衬底温度和溅射功率下制备的AZO薄膜结构、光电性能进行了表征分析.结果表明:各种工艺条件下沉积的AZO薄膜均具有明显的(002)择优取向,没有改变ZnO六方纤锌矿结构;薄膜电阻率随衬底温度升高而减小,随溅射功率增加先减小后增大,衬底温度400℃、溅射功率200W时最小,为1.53×10-5Ω.m;可见光平均透射率均在80%以上,光学带隙与载流子浓度变化趋势一致,最大值为3.52eV.