蒸发速率对ZnS薄膜性能的影响

为了研究蒸发速率对ZnS薄膜的折射率、表面形貌和应力等性能的影响,本文采用电子束蒸发技术进行了ZnS薄膜的制备。首先在K9玻璃基片上镀制薄膜,采用分光光度计进行透射率曲线的测试,利用光谱反演法得出薄膜的折射率,采用原子力显微镜表征了样品的表面形貌。最后在聚酰亚胺基底上镀制薄膜,利用Stoney公式计算出薄膜的应力。结果表明,随着蒸发速率的增加,薄膜折射率先增大后减小,在2000nm波长处薄膜的折射率最大值为2.21,最小值为2.07。蒸发速率越大,薄膜样品表面结构越疏松。不同蒸发速率下制备的薄膜均呈现压应力,增大蒸发速率可以显著降低薄膜应力。ZnS薄膜的性能受蒸发速率影响显著,蒸发速率为1.5nm/s时折射率可达到最大值,蒸发速率为2.5nm/s时薄膜应力最小。     

氧离子能量对离子束辅助沉积Al2O3薄膜的结构及光学性能的影响

利用氧离子束辅助脉冲反应磁控溅射技术在聚酰亚胺基底上沉积Al2O3薄膜。这项技术在溅射高纯铝靶材的同时利用低能氧离子进行氧化来控制薄膜的化学配比。研究了薄膜沉积过程中离子束辅助的作用以及离子束放电电压对Al2O3薄膜的化学成分、结构、表面形貌、光学性能以及沉积速率的影响。结果发现,离子束放电电压对薄膜的化学成分具有显著影响,当电压增加到200 V,薄膜已基本达到完全化学计量比且薄膜为非晶结构;薄膜表面粗糙度随着离子束放电电压的增加而减小,当电压达到300V时,薄膜具有最小的表面粗糙度;通过对Al2O3薄膜透射谱的测量,分析薄膜的光学特性,获得了薄膜的光学常数随离子束放电电压的变化规律,发现氧离子束辅助沉积的薄膜具有较高的折射系数和较低的消光系数;另外,薄膜的沉积速率在电压增加到300V时达到最大值70 nm/min,是未采用离子束辅助时沉积速率的5倍。     

化学水浴法制备ZnS薄膜光学性能

利用薄膜分析系统测量不同沉积时间制备的ZnS薄膜透射谱,通过分析薄膜透射谱,来确定ZnS薄膜光学常数和禁带宽度.实验结果表明,在线性生长阶段,薄膜的沉积速率大约为1 nm/min,具有很好的线性关系,沉积0.5 h的ZnS薄膜在可见光范围内光透过率为82%左右.     

离子束溅射制备Si／Ge多层膜研究

采用离子束溅射方法在Si衬底上制备Si／Ge多层膜，通过改变生长温度、溅射速率等因素得到一系列Si／Ge多层膜样品；通过X射线衍射、Raman散射等表征方法研究薄膜结构与生长条件的关系。在小束流（10mA）、室温条件下制备出界面清晰、周期完整的Si／Ge多层膜。     

衬底温度对柔性硫化锌薄膜结构与光学性能的影响北大核心CSCD

本文利用射频磁控溅射薄膜沉积技术在柔性聚酰亚胺(PI)、氧化铟锡(ITO)玻璃及石英玻璃衬底上制备了透明硫化锌(ZnS)薄膜。通过改变生长过程中的衬底温度,全面系统地研究了衬底温度对柔性和刚性ZnS薄膜的晶体结构、光透过率、光学常数以及表面性能影响的规律。研究表明升高衬底温度有利于形成ZnS薄膜(111)晶面的择优取向生长。不同衬底温度条件下制备的柔性和刚性ZnS薄膜在可见光波长范围内的平均光透过率均大于80%;在红外波长范围的平均光透过率达到85%。柔性ZnS薄膜在400 nm-890 nm波长范围内的光学折射率为2.21-2.56。刚性ZnS薄膜的光学折射率随着衬底温度的升高有所增加,当衬底温度为300℃时,刚性ZnS薄膜在890 nm波长处的折射率达到2.26。柔性ZnS薄膜厚度及表面粗糙度均随着衬底温度的升高而降低,当衬底温度为300℃时,柔性ZnS薄膜表面均方根粗糙度达到最小值2.99 nm。为实现高性能柔性ZnS光电器件,应控制生长柔性ZnS薄膜的衬底温度在200℃-300℃,以获得最优化的器件性能。     

离子束溅射生长Ge纳米薄膜的表面形貌观察

采用离子束溅射技术并按正交试验方案生长了不同厚度以及在不同条件下退火的Ge纳米薄膜,用AFM图谱对薄膜的表面形貌进行了表征.结果表明厚度为2.8nm的Ge膜在600℃下退火10min,出现了高4nm、直径50nm左右的Ge岛,而10nm厚的Ge膜在720℃下退火120min,岛的数量较多且分布比较均匀.通过离子束溅射机理和沉积原子之间的扩散运动,对这些现象进行了较为合理的解释.     

离子束溅射沉积Fe/Si多层膜法合成β-FeSi_2薄膜的研究

采用离子束溅射沉积Fe/Si多层膜的方法在石英衬底上制备了β-FeSi2薄膜,研究了不同厚度比的Fe/Si多层膜对β-FeSi2薄膜的结构性能、形貌及光学性能的影响。结果表明,厚度比为Fe(2nm)/Si(7.4nm)的多层膜在退火后完全生成了β-FeSi2相,表面致密均匀,其光学带隙为0.84eV,能量为1.0eV光子的吸收系数105cm-1。     

化学气相沉积法ZnS块材料的生长

本文用化学气相沉积法制备了ZnS薄膜和块材料;观察了ZnS在具有不同表面粗糙度的石墨和石英基体上的成核和长大行为;研究了沉积温度、H₂S和Zn蒸汽流量对ZnS生长速率的影响规律．     

单层二氧化铪（HfO2）薄膜的特性研究

利用电子束蒸发、离子束辅助沉积和离子束反应溅射三种制备方法制备了单层HfO2薄膜,对薄膜样品的晶体结构、光学特性、表面形貌以及吸收特性进行了研究。实验结果表明,薄膜特性与制备工艺有着密切的关系。电子束蒸发和离子束反应溅射制备的薄膜为非晶结构,而离子束辅助制备的薄膜为多晶结构。电子束蒸发制备的薄膜折射率较低,薄膜比较疏松,表面粗糙度较小,吸收相对较小,而离子束辅助以及离子束反应溅射制备的薄膜折射率较高,薄膜的结构比较致密,但表面粗糙度较大,吸收相对较大。不同制备工艺条件下薄膜的光学能隙范围为5.30～5.43eV,对应的吸收边的范围为228.4～234.0nm。     

热蒸发沉积TiO_2薄膜的光学及激光损伤特性

采用电子束热蒸发技术,用不同沉积速率制备了TiO_2薄膜。根据透射率谱计算了薄膜的光学带隙,采用椭偏法测量了薄膜的折射率、消光系数及厚度,分析了薄膜内部的电场强度分布,对其激光损伤特性进行了研究。结果表明,在所研究的工艺参数范围内,TiO_2薄膜的光学带隙比较稳定,随沉积速率的变化并不显著,其值大小在3.95eV-3.97eV。当沉积速率从0.088nm/s,0.128nm/s增加到0.18nm/s时,薄膜折射率从1.9782,1.9928,升高到2.0021(波长1064nm),但当沉积速率继续增加到0.327nm/s时,折射率反而降低到1.9663,薄膜的消光系数随着沉积速率的增加单调增加。采用同一高能激光损伤薄膜后,当沉积速率较低时制备薄膜的损伤斑大小基本一致,但以0.327nm/s较高速率制备的薄膜,其损伤斑明显增大。高沉积速率下制备的TiO_2薄膜的吸收较大,激光损伤阈值较低。     

High mobility, transparent, conducting Gd-doped In2O3 thin films by pulsed laser deposition

Highly transparent and conducting thin films of gadolinium doped indium oxide, which have high electron mobility, were deposited on quartz substrate to study the effect of growth temperature and oxygen pressure on their structural, optical, and electrical properties. X-ray diffraction study reveals that these films are randomly oriented on the quartz surface. The average particle size of the films grown at 600 °C was calculated to be ∼ 23 nm. The optical transparency of the films increases with an increase in the growth temperature. The film transparency is also found to increase with increased oxygen pressure during deposition. The electrical properties of these films strongly depend on both the growth temperature and the oxygen pressure. Analysis of the electrical data shows that the mobility of the films increases with increase in the growth temperature.     

温度对化学水浴法制备ZnS薄膜的影响

采用化学水浴法在玻璃上制备了太阳能电池中的ZnS缓冲层。采用SEM、EDS、XRD和nkd-分光光度计等手段研究了水浴温度对ZnS薄膜的表面形貌、结构和光学性能的影响。结果表明,升高温度不能明显改变薄膜的结晶性、形貌和沉积生长方式,能否成膜与温度的关系也不大,但成膜速率对温度的依赖性较大。随温度的升高,薄膜的透过率先减小后增大,反射率则先增大后减小。对同一试样而言,透过率和反射率对应较好。当温度为70℃时,可制得禁带宽度为3.83eV、符合化学计量比、平整的非晶ZnS薄膜。     

Substrate temperature influence on ZnS thin films prepared by ultrasonic spray

ZnS thin films were deposited by ultrasonic spray technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 250 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition and optical properties of ZnS films. The DRX analyses indicated that ZnS films have nanocrystalline hexagonal structure with (002) preferential orientation and grain size varied from 20 to 50 nm, increasing with substrate temperature. The optical films characterization was carried out by the UV-visible transmission. The optical gap and films disorder were deduced from the absorption spectra and the refractive indices of the films were determined by ellipsometric measurements. It is shown that the obtained films are generally composed of ZnO and ZnS phases with varied proportion, while at deposition temperature of 400 °C, they are near stoichiometric ZnS.     

Preparation and characterization of ZnS thin films by the chemical bath deposition method

ZnS thin films prepared on quartz substrates by the chemical bath deposition (CBD) method with three type temperature profile processes have been investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis and light transmission. One is a 1-step growth process, and the other is 2-steps growth and self-catalyst growth processes. The surface morphology of CBD-ZnS thin films prepared by the CBD method with the self-catalyst growth process is flat and smooth compared with that prepared by the 1-step and 2-steps growth processes. The self-catalyst growth process in order to prepare the particles of ZnS as initial nucleus layer was useful for improvement in crystallinity of ZnS thin films prepared by CBD. ZnS thin films prepared by CBD method with self-catalyst growth process can be expected for improvement in the conversion efficiency of Cu(InGa)Se₂-based thin film solar cells by using it for the buffer layer.     

The influence of deposition parameters on the optical properties and growth of ZnS films

A vacuum automatic ellipsometer was used to observe and reveal the effect of the rate of deposition on the structural irregularities of ZnS films during growth.The high accuracy and sensitivity of this instrument were exploited for measuring the refractive index of ZnS films prepared at various rates of deposition and substrate temperatures.     

Effects of substrate parameters on structure and optical properties of ZnO thin films fabricated by pulsed laser deposition

Highly oriented zinc oxide thin films have been grown on quartz, Si (1 1 1) and sapphire substrates by pulsed laser deposition (PLD). The effect of temperature and substrate parameter on structural and optical properties of ZnO thin films has been characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), optical transmission spectra and PL spectra. The experimental results show that the best crystalline thin films grown on different substrate with hexagonal wurtzite structure were achieved at growth temperature 400–500 °C. The growth temperature of ZnO thin film deposited on Si (1 1 1) substrate is lower than that of sapphire and quartz. The band gaps are increasing from 3.2 to 3.31 eV for ZnO thin film fabricated on quartz substrate at growth temperature from 100 to 600 °C. The crystalline quality and UV emission of ZnO thin film grown on sapphire substrate are significantly higher than those of other ZnO thin films grown on different substrates.     

Sputter deposition of ZnS:Mn/SrS:Ce multilayered thin film white phosphor

A full color thin film electroluminescent (TFEL) display can be fabricated by using color filters in combination with a high efficiency ‘white’ phosphor, such as a thin film multilayered stack of ZnS:Mn and SrS:Ce (denoted ZnS:Mn/SrS:Ce). To date, deposition of these multilayers has been limited to vacuum evaporation techniques and atomic layer epitaxy, both of which require different substrate temperatures for growth of high quality ZnS:Mn and SrS:Ce. This repeated thermal cycling during multilayer deposition can adversely affect electroluminescent (EL) performance and manufacturability. Sputter deposition of ZnS:Mn and SrS:Ce produces high quality phosphors for a wider range of substrate temperatures. We have determined a common set of radio frequency (rf) sputter deposition parameters for ZnS:Mn and SrS:Ce that result in high performance, multilayered white phosphors for use in TFEL devices. The EL performance of our samples is comparable to the best performance reported for evaporated multilayered samples. The major improvement is that the rf sputtered ZnS:Mn and SrS:Ce layers were deposited at the same substrate temperature. We report on the effects of sputter deposition parameters on the resultant composition and morphology of ZnS:Mn and SrS:Ce thin films and multilayers. Their EL performance was evaluated and correlated to composition and morphology.     

Anisotropic spin transport in oriented lithium phthalocyanine thin films

Thin films of monolithium phthalocyanine (PcLi) were prepared by vacuum deposition on various substrates: cleaved mica, quartz glass, and drawn sheets of poly(tetrafluoroethylene). The highly anisotropic spin transport in these films was studied by electron spin resonance (ESR) as a function of film preparation (thickness and substrate temperature), orientation, and temperature. Transmission electron microscopy confirms the existence of enhanced orientation which can be controlled by adjusting the substrate temperature T_s during film deposition. For low substrate temperatures, homogeneous films with no azimuthal orientation are formed. Above 400 K, epitaxial growth on mica leads to rectangular wedge-shaped crystals. Raising the temperature T_s does not improve the orientation but creates a more discontinuous coverage of the substrate and reduces the electronic relaxation times T₁ and T₂, as monitored by ESR. When increasing the film thicknesses, a steady change towards the bulk properties is demonstrated by the decreasing ESR linewidth.     

透明导电InSnGaMo氧化物薄膜光电性能研究

利用脉冲激光沉积法在石英衬底上制备出了可见光透过率高、电阻率极低的Ga,Mo共掺杂ITO基InSnGaMo复合氧化物薄膜。研究了衬底温度对薄膜结构、表面形貌、光电性能的影响。实验结果表明:衬底温度对InSnGaMo复合氧化物薄膜形貌、光电性能均有很大影响。X射线衍射、扫描电镜和霍尔测试结果表明,随着衬底温度的升高,薄膜晶粒度增大,电阻率快速下降,可见光平均透过率明显提高。当衬底温度为450℃时,InSnGaMo复合氧化物薄膜的电阻率最低为4.15×10-4Ω.cm,载流子浓度和迁移率最大分别为3×1020cm-3,45 cm2V-1s-1,在可见及近红外区平均透过率达92%,特别地,波长为362 nm时,最高透射率可达99%。     

Growth of pseudocubic perovskite-type SrRuO3 thin films on quartz substrate using pulsed laser deposition method

Strontium ruthenium oxide (SrRuO₃) thin films have been grown using pulsed laser deposition technique on silicon, Pt coated silicon and quartz substrates. The effect of substrate temperatures on the structural, microstructure, and electrical properties of the SrRuO₃ films on quartz substrate has been investigated using XRD, SEM, AFM and four-probe method, respectively. The lowest resistivity at room temperature for the SrRuO₃ thin film on quartz substrate has been achieved at substrate temperature of 700 °C. Furthermore, the comparisons of SrRuO₃ thin films deposited on various substrates have been done with respect to structural, microstructural and electrical properties. XRD patterns exhibit that all thin films are a single phase, pseudo-cubic perovskite structure. Study of surface morphology shows that grain size and roughness varies with respect to substrate. It is observed that SrRuO₃ thin films yield larger grain size and root mean square roughness on Pt/Si substrate. Investigation of electrical properties shows that SrRuO₃ thin films can serve the purpose of the bottom electrode in dielectric and ferroelectric devices.