溅射条件对ZnS薄膜的光学常量和微结构的影响

为了研究制备条件对射频溅射ZnS薄膜光学常量和微结构的影响,在浮法玻璃上制备了不同溅射气压、溅射功率和溅射温度的ZnS薄膜,利用紫外可见近红外分光光度计在300～2 500 nm的波长范围内测量了薄膜的透射和反射光谱,并通过光谱拟和计算出ZnS薄膜的光学常量以及禁带宽度.通过X射线衍射分析了薄膜的微结构随溅射温度的改变.研究结果表明,随着制备条件的不同,ZnS薄膜的光学常量和微结构会发生变化.     

退火温度和溅射时间对磁控溅射法制备Mg2Si薄膜的影响

采用磁控溅射法和原位退火工艺在钠钙玻璃衬底上制备 Mg2Si 薄膜。首先在钠钙玻璃衬底上交替溅射沉积两层Si、Mg 薄膜,冷却至室温后原位退火4 h,制备出一系列 Mg2Si 薄膜样品。通过 X 射线衍射仪(XRD) 、 扫描电子显微镜(SEM)对所得薄膜样品的晶体结构和表面形貌进行表征, 讨论了退火温度和溅射Si/Mg/Si/Mg 时间对制备 Mg2Si 薄膜的影响。结果表明,采用磁控溅射法在钠钙玻璃衬底上交替溅射两层Si、Mg 薄膜, 通过原位退火方式成功制备出单一相的 Mg2Si 薄膜,溅射Si/Mg/Si/Mg 的时间为12.5/9/12.5/9 min,退火温度为550 ℃ 时,制备的 Mg2Si 薄膜结晶度最好,连续性和致密性最强。这对后续 Mg2Si 薄膜器件的设计与制备提供了重要的参考。 积两层Si、Mg 薄膜, 冷却至室温后原位退火4 h, 制备出一系列 Mg2Si 薄膜样品. 通过 X 射线衍射仪(XRD) 、 扫描 电子显微镜(SEM)对所得薄膜样品的晶体结构和表面形貌进行表征, 讨论了退火温度和溅射Si/Mg/Si/Mg 时间 对制备 Mg2Si 薄膜的影响. 结果表明, 采用磁控溅射法在钠钙玻璃衬底上交替溅射两层Si、Mg 薄膜, 通过原位退火 方式成功制备出单一相的 Mg2Si 薄膜, 溅射Si/Mg/Si/Mg 的时间为12.5/9/12.5/9 min, 退火温度为550 ℃ 时, 制 备的 Mg2Si 薄膜结晶度最好, 连续性和致密性最强. 这对后续 Mg2Si 薄膜器件的设计与制备提供了重要的参考.     

离子束溅射沉积Ti-Ni薄膜及其电化学性能的研究

利用离子束溅射沉积的方法在不同基片温度条件下制备了不同成分的Ti-Ni贮氢薄膜，研究了其电化学贮氢性能。结果表明：用离子束溅射沉积制备的Ti-Ni薄膜的结构为非晶状，薄膜对基片的附着力较强，在冲放电循环50次后仍为非晶态；在基片温度为350℃时制备的薄膜的结构为晶态，在多次放电循环后呈现非晶化趋势；Ti-Ni薄膜具有较高的电化学活性，晶化薄膜比晶态薄膜的最大放电容量高，但晶化薄膜的循环稳定性差。     

薄膜系列实验的教学研究

从薄膜制备、生长过程动态分析以及形貌表征3方面设计了薄膜系列实验.用离子束溅射制备金属薄膜,研究了制备条件对溅射速率的影响,测量了薄膜生长过程中电阻的变化,用扫描隧道显微镜或原子力显微镜观测薄膜的表面形貌,并分析不同制备条件得到的薄膜的表面形貌特征.     

Sb_2Te_3热电薄膜的离子束溅射制备与表征

采用离子束溅射技术交替沉积Sb-Te-Sb多层薄膜后进行高真空热处理,直接制备Sb2Te3薄膜.利用X射线衍射(XRD)仪、霍尔系数测试仪、薄膜Seebeck系数测量系统对所制备的薄膜特性进行表征.XRD测量结果显示,薄膜的主要衍射峰与Sb2Te3标准衍射峰相同,在[101]/[012]晶向取向明显,存在较多的Te杂质峰;霍尔系数测试结果表明,薄膜为p型半导体薄膜,薄膜电阻率较低,其电导率接近于金属电导率,载流子浓度量级为1023cm-3,具有良好的电学性能;Seebeck系数测量结果显示,薄膜具有良好的热电性能,在不同条件下制备的薄膜的Seebeck系数在7.8—62μV/K范围;在所制备的薄膜中,退火时间为6h、退火温度为200℃的薄膜其Seebeck系数达到最大,约为62μV/K,且电阻率最小.     

高矫顽力和大矩形比钡铁氧体垂直磁记录薄膜

用对向靶直流溅射系统制备了c轴垂直取向的钡铁氧体薄膜.用少量的Al来取代Fe,从而制备了成分为BaAlxFe12-xO19(x=0,1,2)的钡铁氧体薄膜.研究了Al取代Fe对其结晶学性能、磁学性能的影响.研究了退火效应及基板温度对薄膜性能的影响.获得了c轴垂直取向的具有高矫顽力和大矩形比的钡铁氧体薄膜 关键词： 钡铁氧体薄膜 铝取代 高矫顽力 大矩形比     

CdTe太阳电池背接触层的XPS研究

采用共蒸发法在不同条件下制备了ZnTe和ZnTe∶Cu多晶薄膜,通过XRD和XPS研究了它们的结构和各元素的浓度分布。结果表明,不同衬底温度下沉积的薄膜,结构无明显变化,利用XPS溅射剖析获得了薄膜中各成分浓度随溅射时间变化的分布图,发现不同条件下制备的薄膜,溅射速率不同,各成分随溅射时间的变化也不相同。薄膜中Cu的浓度随溅射时间增加而快速增加,并达到一极大值,然后快速下降。根据Cu浓度的变化研究了ZnTe层对Cu原子的阻挡作用,通过对Cu浓度随时间变化分布图的比较,作者认为,用70 ℃制备ZnTe,而后在常温下制备ZnTe∶Cu的复合膜作为CdTe太阳电池的背接触层,能有效阻挡Cu原子的扩散,提高电池效率。     

FTIR法研究BCN薄膜的内应力

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N₂)为工作气体,在Si(100)衬底上制备出硼碳氮(BCN)薄膜。利用傅里叶变换红外光谱(FTIR)考察了不同沉积参数(溅射功率为80～130 W、衬底温度为300～500 ℃、沉积时间为1～4 h)条件下制备的薄膜样品。实验结果表明,所制备薄膜均实现了原子级化合。并且沉积参数对BCN薄膜的生长和内应力有很大影响,适当改变沉积参数能有效释放BCN薄膜的内应力。在固定其他条件只改变一个沉积参数的情况下,得到制备具有较小内应力的硼碳氮薄膜的最佳沉积条件：溅射功率为80 W、衬底温度为400 ℃、沉积时间为2 h。     

SiO2薄膜的制备方法与性质

本文采用光电子能谱和扫描电镜方法研究了溅射沉积条件对SiO2薄膜的表面上的针孔、薄膜原子结构的影响,并分析了不同条件下制备的SiO2薄膜中电子的输运过程.     

溅射条件对Ni80Fe20薄膜各向异性磁电阻的影响

研究了基片温度和溅射气压对磁控溅射方法制备的Ni80Fe20磁性薄膜各向异性磁电阻的影响.实验发现基片温度是影响Ni80Fe20薄膜各向异性磁电阻最重要的因素.在较高的基片温度下,溅射气压对Ni80Fe20薄膜各向异性磁电阻也有较大的影响.基片温度在150~180℃,溅射气压在0.3~0.5 Pa范围内制备的Ni80Fe20薄膜有较大的各向异性磁电阻(3.7%~4.3%).     

Effect of annealing conditions on structural and magnetic properties of laser ablated copper ferrite thin films

The effect of annealing conditions on structural and magnetic properties of copper ferrite thin films on (100) Si substrates was examined in detail. After deposition, the ferrite thin films were post-annealed in vacuum and in oxygen atmosphere for several hours. It is found that the crystal structure of CuFe₂O₄ thin films changed drastically depending on different heating process. A maximum magnetization was achieved in the film that was vacuum annealed and it decreased remarkably after oxygen annealing.     

Barium ferrite films with in-plane orientation grown on silicon by pulsed laser deposition

For the first time, barium ferrite films with in-plane orientation were prepared at 700°C by pulsed laser deposition technique (PLD) on Si(1 1 1) without any post-annealing. An amorphous Ba–Fe–O film is used as underlayer to facilitate the crystallization and improve the orientation of films. Sharp (1 1 0) and (2 2 0) peaks appeared in the XRD pattern. The surface morphologies observed by SEM are similar to the typical computer generated grain arrangements obtained by Suzuki et al. in their micromagnetics study. Furthermore, a particular kind of structure of film cross-section was identified in PLD for barium ferrite films. The grain size is about 3 μm, and the coercivity is around 1500 Oe.     

Effects of annealing in nitrogen atmosphere and HCl-etching on the photoluminescence spectra of spray-deposited CdS:In thin films

The aim of this work is to find the effect of processing on the photoluminescence (PL) of spray-deposited CdS:In thin films. So the PL spectra of the as-deposited, annealed and HCl-etched CdS:In thin films prepared by the spray pyrolysis (SP) technique were recorded at T = 23 K. The yellow and red bands were observed in the spectrum of the as-deposited film beside bands with weaker intensity in the infrared region. The PL signal was weakened by annealing in nitrogen atmosphere at T = 400 °C and HCl-etching. A deconvolution peak fit was established to find the effects of these treatments on the different bands. The spectrum of the as-deposited film was deconvoluted to 12 peaks, which were reduced to 6 peaks after both treatments. It was found that both treatments have approximately the same effects on the PL spectra; that is they removed most of the peaks and shoulders in the red and infrared regions and attenuated most of the peaks in the yellow region. Some peaks were blue-shifted after annealing which was explained by the growth of nanocrystallites due to the thermal stress that results from the different expansion coefficients of the film and the substrate. These changes were accompanied by a phase change from the mixed (cubic and hexagonal) phase to the hexagonal phase as shown in the X-ray diffractograms.     

Dispersion of laser droplets using H+ ions and annealing effect on pulsed laser deposited nickel ferrite thin films

Nickel ferrite thin films were deposited by a pulsed laser deposition (PLD) technique on silicon substrate at room temperature in a vacuum of 5×10⁻⁵ mbar. The films were subjected to different annealing temperatures from 300–900°C and were also exposed to single shot energetic hydrogen ions using a Dense Plasma Focus (DPF) device. The changes induced in the films exposed at different distances from the top of the anode were investigated. The structural, morphological and magnetic properties of the annealed and exposed samples were investigated. X-ray diffraction (XRD) studies reveal the presence of a single phase of nickel ferrite after annealing. SEM micrographs indicate an increase in the grain size, both on annealing as well as on exposure to hydrogen ions. Annealing and hydrogen ion irradiation induced an enhancement in the magnetic moments. Laser droplets which are inherent in films deposited by laser ablation were found to be dispersed as a result of single shot hydrogen ion irradiation from the DPF.     

Interaction effects in magnetic oxide nanoparticle systems

The interaction effects in magnetic nanoparticle system were studied through a Monte Carlo simulation. The results of simulations were compared with two different magnetic systems, namely, iron oxide polymer nanocomposites prepared by polymerization over core and nanocrystalline cobalt ferrite thin films prepared by sol-gel process. The size of the particles in the nanocomposites were estimated to be ∼15 nm with very little agglomeration. The low values of the coercivity obtained from the hysteresis measurements performed confirm that the system is superparamagnetic. SEM studies showed the cobalt ferrite films to have a nanocrystalline character, with particle sizes in the nanometer range. Hysteresis measurements performed on the thin films coated on silicon do not give evidence of the superparamagnetic transition up to room temperature and the coercivity is found to increase with decreasing film thickness. Comparison with simulations indicate that the nanocomposites behave like a strongly interacting array where exchange interactions lead to high blocking temperatures, whereas the films are representative of a semi-infinite array of magnetic clusters with weak interactions and thickness-dependent magnetic properties.     

Thermostabilization of magnetostatic wave frequency and group velocity in a cubic ferrite film

The conditions for thermostability of the group velocity and frequency of magnetostatic waves in a ferromagnetic layer were studied theoretically. The temperature dependence of the bias field parameters was determined from the conditions for simultaneous thermostability of the frequency and group velocity. Particular emphasis was placed on ferrite films with cubic anisotropy.     

Effects of cooling rate and post-heat treatment on properties of ZnO thin films deposited by sol-gel method

Sol-gel spin-coated ZnO thin films are cooled with different rates after the pre-heat treatment. Atomic force microscopy (AFM), X-ray diffraction (XRD), Raman, and photoluminescence (PL) were carried out to investigate the effects of the cooling rate during pre-heat treatment on structural and optical properties of the ZnO thin films. The ZnO thin films cooled slowly exhibit mountain chain structure while the ones cooled rapidly have smooth surface. The ZnO thin films cooled rapidly have higher c-axis orientation compared to the ones cooled slowly. The narrower and the higher near-band-edge emission (NBE) peaks are observed in the ZnO thin films cooled rapidly.     

Au/SiO2纳米多层薄膜的制备及其性质表征

利用多靶磁控溅射技术制备了Au/SiO₂纳米颗粒分散氧化物多层复合薄膜.研究了在保持Au单层颗粒膜沉积时间一定时薄膜厚度一定、变化SiO₂的沉积时间及SiO₂的沉积时间一定而改变薄膜厚度时，多层薄膜在薄膜厚度方向的微观结构对吸收光谱的影响.研究结果表明：具有纳米层状结构的Au/SiO₂多层薄膜在560 nm波长附近有明显的表面等离子共振吸收峰，吸收峰的强度随Au颗粒的浓度增加而增强，在Au颗粒浓度相同的情况下，复合薄膜 关键词： 2纳米复合薄膜')" href="#">Au/SiO₂纳米复合薄膜 多靶磁控溅射 吸收光谱 有效介质理论     

Effect of nonstoichiometry on Raman scattering of VO2 films

We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.     

Temperature-dependent photoluminescence spectra of GaN epitaxial layer grown on Si(111) substrate

In this paper, the temperature-dependent photoluminescence(PL) properties of Ga N grown on Si(111) substrate are studied. The main emission peaks of Ga N films grown on Si(111) are investigated and compared with those grown on sapphire substrates. The positions of free and bound exciton luminescence peaks, i.e., FX A and D0 X peaks, of Ga N films grown on Si(111) substrates undergo red shifts compared with those grown on sapphire. This is attributed to the fact that the Ga N films grown on sapphire are under the action of compressive stress, while those grown on Si(111) substrate are subjected to tensile stress. Furthermore, the positions of these peaks may be additionally shifted due to different stress conditions in the real sample growth. The emission peaks due to stacking faults are found in Ga N films grown on Si(111) and an S-shaped temperature dependence of PL spectra can be observed, owing to the influence of the quantum well(QW) emission by the localized states near the conduction band gap edge and the temperature-dependent distribution of the photo-generated carriers.