沉积时间对脉冲激光沉积法制备ZnO薄膜性能的影响

采用脉冲激光沉积技术(PLD)在氧气气氛中以高纯Zn为(99.999%)靶材,在单晶硅和石英衬底表面成功生长了ZnO薄膜.通过X射线衍射仪、表明轮廓仪、荧光光谱仪、紫外可见分光光度计对合成薄膜材料的晶体结构、厚度、光学性质等进行了研究,分析了ZnO薄膜的沉积时间对其性能的影响.结果表明,采用PLD法在室温下可以制备出(002)结晶取向和透过率高于75%的ZnO薄膜,但室温下沉积的ZnO薄膜的发射性能较差,沉积时间的延长不能改善薄膜的发光性能.     

脉冲激光沉积ZnO及其掺杂薄膜的研究

本文用脉冲激光沉积（PLD）法在SiO2基片上制备了ZnO薄膜和Zn1-xMnxO薄膜。X射线衍射、原子力显微镜、紫外-可见分光光度计对ZnO薄膜的测试结果表明：薄膜具有（103）面的择优取向，表面比较平坦；SiO2基片上制备的薄膜在387nm附近存在明显的吸收边，且薄膜的吸收对基片温度变化不明显。通过对Zn1-xMnxO薄膜的吸收光谱分析得出：Mn离子的掺杂改变了ZnO薄膜的禁带宽度，随Mn离子的掺杂量的增加，薄膜禁带宽度增加；薄膜的光吸收也从直接跃迁过渡为间接跃迁过程。     

氮化硅减反射膜制备工艺对组织结构及折射率影响的研究

太阳能电池是一种清洁能源, 近年来发展迅猛。减反射膜能大幅减少太阳能电池对光线的反射, 从而提高电池光电转化率。为优化减反射效果, 减反射膜设计多样, 包括单层膜、双层膜、三层膜和多层膜, 膜层不同对薄膜材料的折射率要求不同。氮化硅薄膜是一种优秀的硅基太阳能减反射膜, 其折射率在1.78~2.5之间, 调控范围广。本文采用脉冲激光沉积法制备氮化硅减反射膜, 研究不同工艺参数对硅片上沉积的氮化硅薄膜性能的影响。     

脉冲激光沉积法室温下ZnO薄膜的制备与表征

在室温条件下,采用脉冲激光沉积技术在玻璃衬底上生长了ZnO薄膜.对薄膜的XRD分析表明,ZnO薄膜为六方纤锌矿结构并沿c轴取向生长,且(002)衍射峰的半高峰宽仅为0.24°.薄膜沿c轴方向受到一定的张应力为1.7×108 N/m2.原子力显微镜分析表明薄膜表面较为平整,平均粗糙度约为6.5 nm,晶粒尺寸约为50 nm.此外,透射光谱分析表明薄膜的禁带宽度为3.25 eV,与ZnO体材料的禁带宽度3.30 eV基本相同.     

衬底温度对PLD方法生长的ZnO薄膜结构和发光特性的影响

在不同的衬底温度下, 通过脉冲激光淀积的方法在Si衬底上生长出c轴高度取向的ZnO薄膜. ZnO薄膜的结构和表面形貌通过X射线衍射和原子力显微镜表征. 同时以He-Cd激光和同步辐射作为激发源来测试样品的发光特性. 实验结果表明, 在衬底温度为500℃时生长的ZnO薄膜具有非常好的晶体质量, 并且表现出很强的紫外发射. 在用同步辐射为激发源的低温(18K)光致发光谱中, 还观察到了一个位于430nm处的紫光发射, 我们认为这个紫光发射与存在于晶粒间界的界面势阱所引起的缺陷态有关, 这个势阱可能起源于Zn填隙(Zn _i)     

Properties of ZnO Thin Films Grown on Si (100) Substrates by Pulsed Laser Deposition

ZnO thin films were grown on Si (100) substrates by pulsed laser deposition using a ZnO target.The substrate temperature was varied in the range of room temperature to 800 ℃,and the oxygen partial pressure of 0.1333 Pa (1 m Torr) to 1333 Pa (10 Torr).The properties of the resulting films were investigated by photoluminescence (PL),grazing incidence X-ray diffraction (GIXRD),X-ray photoelectron spectroscopy (XPS),and field emission scanning electron microscopy (FESEM).Based on the ultraviolet (UV,～380 nm) to...     

脉冲激光沉积ZnO薄膜的结构和光学特性研究

采用脉冲激光，在Si（001）衬底上生长ZnO薄膜，利用X射线衍射（XRD），原子力显微镜（AFM）和光致发光光谱（PL）等测试手段研究了不同衬底温度所生长的ZnO薄膜结构特征和光学性能。研究表明：衬底温度影响ZnO薄膜结构和光学性能。在500℃～600℃沉积范围内随着温度升高，ZnO薄膜结构和光学性能提高。     

Structural and functional properties of Al:ZnO thin films grown by Pulsed Laser Deposition at room temperature

Current research on transparent conductive oxides (TCOs) is focusing on indium-free TCOs, such as Al-doped ZnO (AZO), as an alternative to indium-tin oxide. In this work, AZO thin films were grown by Pulsed Laser Deposition at room temperature in oxygen atmosphere. The O₂ pressure was varied from 0.01 Pa to 10 Pa, highlighting the effects of defect formation and oxygen vacancies on the film properties. Structural properties were characterized by X-ray diffraction and Scanning Electron Microscopy, while functional properties were characterized by measurement of electrical conductivity, Hall mobility, carrier density and optical transmission. At an optimal deposition pressure of 2 Pa, optical transparency in the visible range and minimum resistivity (4.5 ? 10^− 4 Ω cm) were found, comparable to state-of-the-art TCOs. Mean value of visible transparency was shown to increase with increasing pressure, up to 88% at a deposition pressure of 10 Pa.     

Effect of Annealing on the Optical Properties of GaN Films Grown by Pulsed Laser Deposition

In the present study,gallium nitride thin films were grown by using pulsed laser deposition.After the growth samples were annealed at 400 and 600℃in the nitrogen atmosphere.Surface morphology of the as-grown and annealed samples was observed by atomic force microscopy.Post-growth annealing results in an improved surface roughness of the films.Chemical analysis of the samples was performed by X-ray photoelectron spectroscopy.Stoichiometric gallium nitride thin films were obtained for the samples annealed at 600℃.Optical measurements of the samples were performed to measure the band gap and optical constants of the films.Effect of annealing on the band gap and optical constants of the films was studied.     

PLD法生长高质量 ZnO薄膜及其光电导特性研究

采用脉冲激光沉积（PLD）法在单晶Si（100）衬底上生长ZnO薄膜，以X射线衍射（XRD）和场发射扫描电镜（SEM）等手段分析了所得ZnO薄膜的晶体结构和微观形貌．结果表明，随着衬底温度和薄膜生长时氧分压的增加，ZnO薄膜的晶体结构和化学计量比得到显著改善．优化工艺（700℃，20Pa）下生长的ZnO薄膜呈c轴高度择优取向，柱状晶垂直衬底表面生长，结构致密均匀．以不同暗电阻的ZnO薄膜为材料，利用剥离（1ift-off）技术制备了MSM结构ZnO光电导型紫外探测器．紫外光照射前后的I-V特性测试表明ZnO薄膜产生非常明显的光电导现象，分析了其光电响应机理．     

PLD生长的ZnO薄膜的微结构及其发光特性研究

在不同的衬底温度下，通过脉冲激光淀积（PLD）方法在Si衬底上生长出c轴高度取向的ZnO薄膜。ZnO薄膜的结构分别通过X射线衍射（XRD）和广延X射线吸收精细结构（EXAFS）来表征，而表面成份和化学态则通过X射线光电子能谱来研究。利用光致发光（PL）来研究样品的发光特性。XRD结果和EXAFS结果都表明了500℃时生长的ZnO薄膜的结晶性比300℃时生长的要好。EXAFS结果和XPS结果显示，300℃时生长的ZnO薄膜处于富氧状态，而500℃时生长的则处于缺氧状态。结合XRD谱、EXAFS谱、XPS谱和PL谱的结果可以看到：随着ZnO薄膜的结晶性变好，它的紫外发光增强；另一方面，随着ZnO薄膜中O的含量减少，绿光发射变强。我们的结果表明绿光发射与ZnO中氧空位（V0）有关。     

p型掺杂ZnO薄膜的研究进展

近年来,随着对ZnO的光电性质及其在光电领域应用的开发研究,制备可靠稳定的低阻p型ZnO薄膜成为研究热点之一。本文论述了p型ZnO薄膜制备的难点及其解决方法,综述了其最新研究进展,并对p型ZnO的研究进行了展望。     

Comparative study on Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation of urease thin films

Urease thin films were produced by Matrix Assisted Pulsed Laser Evaporation (MAPLE) and Pulsed Laser Deposition from two types of targets: frozen water solutions of urease with different concentrations (1-10% m/v) and pure urease pellets. The fluence of the ablating KrF excimer laser was varied between 300 and 2200 mJ/cm². Fourier transform infrared spectra of the deposited films showed no difference as compared to the original urease. Morphologic studies proved that the films consist of a smooth “base” layer with embedded micrometer-sized droplets. Absorption-coefficient measurements contradicted the traditional “absorptive matrix” model for MAPLE deposition. The laser energy was absorbed by urease clusters leading to a local heating-up and evaporation of the frozen matrix from the uppermost layer accompanied by the release of dissolved urease molecules. Significant enzymatic activity of urease was preserved only during matrix assisted transfer.     

Synthesis of ZnO nanowire array film on Mg doped gallium nitride substrate

ZnO nanowire array films, composed of well aligned ZnO nanowires ～200?nm in diameter and 1?μm in length, were successfully synthesised on Mg doped gallium nitride by hydrothermal method. In addition, the films possess quite flatten surface. In the synthesised process, there was no catalyst that had been used. Growth conditions were comprehensively discussed in the process of aqueous solution method. It was found that the length of ZnO nanowires and the thickness of the film could be tunable by altering solution concentration and growth time. Such ZnO film assembled with vertically aligned nanowire may have potential applications as UV light emitting diodes.     

Laser ablated ZnO layers for ALGaN/GaN HEMT passivation

ZnO layer in a role of passivation of the AlGaN/GaN-based high electron mobility transistors (HEMTs) is presented. The thin layer is deposited by pulsed laser deposition technique. It is fully compatible with the process technology of high electron mobility transistors prepared on AlGaN/GaN heterostructures due to its physical properties similar to the GaN. We have succeeded to (1) suppress the gate leakage current; (2) increase the maximum of the drain current and the electron drift mobility, and (3) ensure the threshold voltage to be unaltered by employment of the thin ZnO layer to the channel area of the HEMT.     

脉冲激光沉积(PLD)法生长纳米ZnO薄膜的探索

在Si衬底上用脉冲激光沉积法生长C轴取向高度一致的ZnO纳米薄膜.实验制备ZnO纳米结构,其颗粒尺寸的控制是关键.通过改变衬底温度(400～700℃)和沉积时间,获得不同的ZnO纳米结构.SEM观察,在600℃时颗粒均匀且间隔明显,且该薄膜结构为不连续膜,这与其他衬底温度下所形成的薄膜结构有很大差异.XRD显示,600～700℃结晶良好.     

脉冲激光沉积制备ZnO纳米棒的研究进展

综述了脉冲激光沉积法制备ZnO纳米棒的研究进展.介绍了不同制备参数条件下ZnO纳米棒的形貌特征、性质及其生长机理,阐述了利用脉冲激光沉积制备高质量ZnO纳米棒及阵列的条件,为ZnO纳米棒的制备及性质的深入研究提供了有益的参考.     

ZnO薄膜的p型掺杂研究进展

ZnO作为重要的第三代半导体材料在光电领域具有广泛的应用前景因而引起越来越多的关注,ZnO薄膜的p型掺杂是实现ZnO基光电器件的关键,也是ZnO材料的主要研究课题.本文论述了ZnO薄膜P型转变的难点及其解决方法,概述了ZnO薄膜p型掺杂的研究现状,提出了有待进一步研究的问题.     

Effects of laser scans on the diffusion depth and diffusivity of gallium in n-type 4H-SiC during laser doping

An n-type 4H-SiC substrate has been doped with gallium using a continuous wave Nd:YAG laser to heat the sample to high temperatures but below the peritectic temperature of SiC. Mathematical models have been presented for the temperature and Ga concentration distributions in the sample. The Ga atoms, which are produced due to the thermal decomposition of a metallorganic precursor, diffuse into the sample by the solid-phase diffusion process at high temperatures. This process is modeled by considering the temperature-dependent diffusion coefficient and the Ga concentration profile was measured by the secondary ion mass spectrometry (SIMS). The concentration of Ga (6.25 × 10²⁰ cm⁻³) at the substrate surface was found to exceed the solid solubility limit (1.8 × 10¹⁹ cm⁻³) of Ga in SiC. Comparing the SIMS data to the results of the diffusion model, the activation energy, pre-exponential factor and diffusion coefficient of Ga were determined for different doping conditions. Four doped samples were produced by scanning the samples with a laser beam for different number of passes. The sample prepared with four passes showed the highest diffusion coefficient of 5.53 × 10⁻⁷ cm²/s with activation energy 1.84 eV and pre-exponential factor 1.05 × 10⁻² cm²/s. The diffusion coefficient is five orders of magnitude higher than the typical diffusion coefficient of Ga in SiC. This indicates that the laser doping process enhances the diffusion coefficient of dopant significantly.