Photoconductive properties of lead iodide films prepared by electron beam evaporation

Lead iodide (PbI2) films have been prepared by electron beam evaporation technique, and their photoconductive response to visible light was investigated under different deposition and illumination conditions. It is found that the films’ photoconductive response speed increases and the relative sensitivity decreases with the increase of substrate temperature due to the opposite requests for photo-carrier lifetime. Further, appropriately increasing the film’s thickness and rising substrate temperature simultaneously can effectively balance the opposite demands. Under the optimized conditions of substrate temperature of 200℃, source-substrate distance of 30cm and deposition time of 10min, the prepared films exhibit best response properties. In addition, the response to illumination with different wavelengths was also measured, revealing that the decline of response performance with increasing wavelength is due to lower photon energy of incident light.     

Photoconductive properties of lead iodide films prepared by electron beam evaporation

Lead iodide(PbI_2) films have been prepared by the electron beam evaporation technique,and their photoconductive response to visible light was investigated under different deposition and illumination conditions.It is found that the films' photoconductive response speed increases and the relative sensitivity decreases with the increase of substrate temperature due to the opposite requests for photo-carrier lifetime.Further,appropriately increasing the film's thickness and rising substrate temperature simu...     

Effects of Annealing Temperature on Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

ZnO thin films are deposited on n-Si（111） substrates by pulsed laser deposition（PLD） system. Then the samples are annealed at different temperatures in air ambient and their properties are investigated particularly as a function of annealing temperature. The microstructure, morphology and optical properties of the as-grown ZnO films are studied by X-ray diffraetion（XRD）. atomic force mieroseope（AFM）, Fourier transform infrared spectroscopy（FTIR） and photoluminescence（PL） spectra. The results show that the as- grown ZnO films have a hexagonal wurtzite structure with a preferred c-axis orientation. Moreover, the diameters of the ZnO crystallites become larger and the crystal quality of the ZnO fihns is improved with the increase of annealing temperature.     

Optical and Electrical Properties of Polyimide Thin Films Grown by Vapor Deposition Polymerization

Using pyromellitic dianhydride (PMDA) and 4,4' diaminodiphenyl ether (ODA) as monomer materials, polyimide thin films have been prepared onto glass substrate by vapor deposition polymerization under a vacuum of 2.666×10 -3 Pa and thermal curing of polyamic acid film in a vacuum at temperature of 150～200 ℃ for 60 min. In this process, the polymerization can be carried out through controlling the stoichiometric ratio, heating time and deposition ratio of the two monomers. The composition, the structure and properties of the polyimide films are investigated with IR spectrum, XRD, and SEM methods. The results show that the polyimide films by vapor deposition polymerization have good electrical properties and thermal stability. Therefore, the vapor deposition polymerization process is considered as a possible method of polymerization for other polymers.     

衬底温度对In掺杂CdO薄膜的结构和性能的影响

Transparent indium-doped cadmium oxide（In-CdO） thin films were deposited on quartz glass substrates by pulsed laser deposition（PLD） from an ablating Cd-In metallic target.The effect of substrate temperature on the structural,optical and electrical properties of In-doped CdO thin films were studied in detail.The optical transmittance of In doped CdO films are obviously influenced by the substrate temperature.All films exhibit a transmittance higher than 75%in the visible region.More significantly,In-doping leads to an evident widening of optical band gap from 2.56 to 2.91 eV;and the increase in optical band gap is found to depend on the deposition temperature.It is also seen that the electrical properties of these films strongly depend on the substrate temperature. The In-CdO thin film grown at 300℃has low resistivity(1.15×10^-4Ω·cm),high carrier concentration(5.35×10²⁰ cm^-3),and high mobility（101.43 cm²/（V·s））.     

Influence of substrate temperature on the deposition and structural properties of μc-Si: H thin films fabricated with VHF-PECVD

With in situ optical emission spectroscopy (OES) diagnosis on VHF-generated H₂+SiH₄ plasmas, and with the measurements of deposition rate and structure of μc-Si: H thin films fabricated with VHF-PECVD technique at different substracte temperature, influence of substrate temperature on the deposition of μc-Si: H thin film and on its structural properties have been investigated. The results show that with the increase of substrate temperature, the crystalline volume fraction Xc and average grain size d are enhanced monotonously, but the deposition rate increases firstly and then decreases. The optimized substrate temperature for (μc-Si: H thin films deposition under our current growth system is about 210 °C, at which deposition rate 0.8 nm/s of μc-Si: H thin film with Xc?60% and d?9 nm can be obtained.     

Visible photoluminescence from ZnO/diamond-like carbon thin films

ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm, 554 nm and 698 nm. The origin and possible mechanism of the visible PL are discussed, and they can be attributed to the PL recombination of ZnO and DLC thin films.     

Cubic AlN thin film formation on quartz substrate by pulse laser deposition

Cubic AlN thin films were obtained on quartz substrate by pulse laser deposition in a nitrogen reactive atmosphere. A Nd-YAG laser with a wavelength of 1064 nm was used as the laser source. In order to study the influence of the process parameters on the deposited AlN film, the experiments were performed at various technique parameters of laser energy density from 70 to 260 J/cm², substrate temperature from room temperature to 800℃ and nitrogen pressure from 0.1 to 50 Pa. X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy were applied to characterize the structure and surface morphology of the deposited AlN films. It was found that the structure of AlN films deposited in a vacuum is rocksalt under the condition of substrate temperature 600-800℃, nitrogen pressure 10-0.1 Pa and a moderate laser energy density (190 J/cm²). The high quality AlN film exhibited good optical property.     

利用物理气相淀积工艺制备的HfTaON薄膜热力学稳定性研究

We investigate the thermal stability of HfTaON films prepared by physical vapor deposition using high resolution transmission electronic microscope （HRTEM） and X-ray photoelectron spectroscopy （XPS）. The results indicate that the magnetron-sputtered HfTaON films on Si substrate are not stable during the post-deposition annealing （PDA）. HfTaON will react with Si and form the interfacial layer at the interface between HfTaON and Si substrate. Hf-N bonds are not stale at high temperature and easily replaced by oxygen, resulting in significant loss of nitrogen from the bulk film. SiO2 buffer layer introduction at the interface of HfraON and Si substrate may effectively suppress their reaction and control the formation of thicker interfacial layer. But SiO2 is a low k gate dielectric and too thicker SiO2 buffer layer will increase the gate dielectric＇s equivalent oxide thickness. SiON prepared by oxidation of N-implanted Si substrate has thinner physical thickness than SiO2 and is helpful to reduce the gate dielectric＇s equivalent oxide thickness.     

Optical properties of ZnO thin films grown on diamond-like carbon by pulsed laser deposition

ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures.The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum.The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm,526 nm and 682 nm,which are attributed to the radiative recombination of ZnO and DLC,respectively.The Commission International de l,Eclairage(CIE)1931(x,y)chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region.     

脉冲激光沉积法制备ZnO薄膜的研究进展

基于氧化锌薄膜紫外光发光的实现,ZnO薄膜成为新的研究热点。综述了各种沉积条件对脉冲激光沉积(PLD)技术生长的氧化锌薄膜的微结构、光学和电学性质的影响,ZnO薄膜的厚度在超过400 nm时,呈现出了近似块状的性质。采用PLD技术,可以在适当的条件下制备具有特定功能的氧化锌薄膜。     

氧压对ZnO薄膜电阻温度系数的影响

采用脉冲激光沉积(PLD)技术,在不同氧气氛下,在Si(lll)衬底上生长了ZnO薄膜,使用X线衍射仪分析了ZnO薄膜的结晶质量.计算了不同氧气氛下生长的ZnO薄膜的电阻温度系数(TCR)值,发现随着氧分压降低,ZnO薄膜的TCR值增大;ZnO薄膜的TCR值最高可达-8%/K.这为研究ZnO薄膜的导电特性提供了新的途径,开辟了ZnO薄膜在室温非制冷红外微测辐射热计材料中的应用潜力.     

PLD法生长Al_2O_3基ZnO薄膜的特性

在不同衬底温度下,用脉冲激光沉积法(PLD),在Al2O3(0001)平面上生长了ZnO薄膜。研究了衬底温度对其结晶质量、电学性质以及发光性质的影响。结果显示:XRD在2θ为34°处出现了唯一的ZnO(0002)衍射峰;ZnO薄膜的电阻率随衬底温度的升高而增大;在衬底温度为500℃时,出现了位于410nm附近的特殊的光致发光(PL)峰。     

用脉冲激光沉积方法制备的ZnO薄膜的结构及光致发光特性

在从室温到800℃的温度范围内,用脉冲激光沉积方法在Al₂O₃（0001）衬底上制备了ZnO薄膜。采用X射线衍射仪、原子力显微镜以及荧光光谱仪分别研究了衬底温度对ZnO薄膜表面形貌、结晶质量和光致发光特性的影响。X射线衍射仪和原子力显微镜的结果表明,当衬底温度从室温升高到400℃时,ZnO薄膜的结构及结晶质量逐渐提高,而当衬底温度超过400℃时,其结构和结晶质量变差;在400℃下生长的ZnO薄膜具有最佳的表面形貌和结晶质量。室温光致发光的测量结果表明,400℃下生长的ZnO薄膜的紫外发光强度最强,且发光波长最短（386 nm）。     

脉冲激光沉积工艺参数对生物活性薄膜的影响

脉冲激光沉积是近年来出现的一项制备薄膜的新技术,在制备生物活性薄膜方面显示出独特的优越性。介绍了脉冲激光沉积技术的原理及特点,详细综述了反应气氛、衬底温度、激光波长、能量密度、靶材性能、沉积速率及薄膜厚度等工艺参数对羟基磷灰石及生物玻璃薄膜组织及性能的影响,展望了该项技术的应用前景。     

PLD法制备ZnO薄膜的退火特性和蓝光机制研究

通过脉冲激光沉积(PLD)方法,在O2中和100～500℃衬底温度下,用粉末靶在Si(111)衬底上制备了ZnO薄膜,在300℃温度下生长的薄膜在400～800℃温度和N2氛围中进行了退火处理,用X射线衍射(XRD)谱、原子力显微镜(AFM)和光致发光(PL)谱表征薄膜的结构和光学特性。XRD谱显示,在生长温度300℃时获得较好的复晶薄膜,在退火温度700℃时获得最好的六方结构的结晶薄膜;AFM显示,在此退火条件下,薄膜表面平整、晶粒均匀;PL谱结果显示,在700℃退火时有最好的光学特性。     

衬底温度对脉冲激光沉积制备ZnO性能的影响

本文采用脉冲激光沉积（PLD）(KrF准分子激光器：波长248 nm,频率5Hz,脉冲宽度20 ns）方法在氧气气氛中以高纯Zn（99.999%）为靶材、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,分析了衬底温度变化对其性能的影响。实验结果表明我们使用PLD法在室温下可以制备出了高度结晶取向、高透过率和近带边发射的高质量ZnO薄膜。     

Room-temperature ferromagnetic ordering in Mn-doped ZnO thin films grown by pulsed laser deposition

The ferromagnetic ordering in Mn-doped ZnO thin films grown by pulsed laser deposition (PLD) as a function of oxygen pressure and substrate temperature has been investigated. Room-temperature ferromagnetic behaviors in the Mn-doped ZnO films grown at 700°C and 800°C under 10⁻¹ torr in oxygen pressure were found, whereas ferromagnetic ordering in the films grown under 10⁻³ torr disappeared at 300 K. The large positive magnetoresistance (MR), ∼10%, was observed at 5 K at low fields and small negative MR was observed at high fields, irrespective of oxygen pressure. In particular, anomalous Hall effect (AHE) in the Mn-doped ZnO film grown at 700°C under 10⁻¹ Torr has been observed up to 210 K. In this work, the observed AHE is believed to be further direct evidence demonstrating that the Mn-doped ZnO thin films are ferromagnetic.     

激光沉积红外窗口高性能类金刚石膜技术

类金刚石(DLC)膜具有宽光谱高透射率、高硬度、高热传导及高稳定性等优点,是红外窗口增透保护膜的优选,但现有方法制备的类金刚石膜难以满足高马赫数或海上盐雾等恶劣条件下的应用。激光法相比其他制备方法具有诸多优点,介绍了激光法制备DLC膜的原理及特点,并分析了实现工程应用的难题及关键技术。采用激光沉积法制备出综合性能优异的类金刚石膜,纳米硬度高达44 GPa、内应力仅0.8 GPa、临界刮擦载荷附着力为59.1 mN。正面镀DLC膜,背面镀普通增透膜的硫化锌、硅、锗等红外窗口的平均透射率达82%~91%。实现了150 mm基片的激光法大尺寸均匀薄膜,膜厚不均匀性≤±2%。制备的DLC膜红外窗口通过军标环境适应性试验,并已实现工程化应用。     

PECVD沉积微晶硅薄膜过程中氢原子对透明导电膜的影响

研究了等离子体放电过程中氢原子对单层SnO2和SnO2/ZnO双层透明导电膜的影响.发现当衬底温度超过150℃,H等离子体处理使SnO2薄膜的透光率显著降低.当在SnO2薄膜表面沉积一层ZnO时,既使ZnO膜的厚度为50nm,也可有效地抑制H原子对SnO2的还原效应,并在SnO2/ZnO双层膜上制备了转换效率为3.8%的微晶硅薄膜太阳电池.