磁控溅射制备铬薄膜的结构和光电学性质

用直流磁控溅射技术在石英基片上制备不同厚度(5 nm~114 nm之间)的铬膜.使用X射线衍射仪和分光光度计分别检测薄膜的结构和光学性质,利用德鲁特模型和薄膜的透射、反射光谱计算铬膜的厚度和光学常量,并采用Van der Pauw方法测量薄膜电学性质.结果表明:制备的铬薄膜为体心立方的多晶态,随着膜厚的增加,薄膜的结晶性能提高,晶粒尺寸增大;在可见光区域,当膜厚小于32 nm时,随着膜厚的增加,折射率快速减小,消光系数快速增大,当膜厚大于32 nm时,折射率和消光系数均缓慢减小并逐渐趋于稳定;薄膜电阻率随膜厚的增加为一次指数衰减.     

磁控溅射制备铬薄膜的结构和光电学性质(英文)

用直流磁控溅射技术在石英基片上制备不同厚度(5nm～114nm之间)的铬膜.使用X射线衍射仪和分光光度计分别检测薄膜的结构和光学性质,利用德鲁特模型和薄膜的透射、反射光谱计算铬膜的厚度和光学常量,并采用Van der Pauw方法测量薄膜电学性质.结果表明:制备的铬薄膜为体心立方的多晶态,随着膜厚的增加,薄膜的结晶性能提高,晶粒尺寸增大;在可见光区域,当膜厚小于32nm时,随着膜厚的增加,折射率快速减小,消光系数快速增大,当膜厚大于32nm时,折射率和消光系数均缓慢减小并逐渐趋于稳定;薄膜电阻率随膜厚的增加为一次指数衰减.     

基于小波变换的油膜光谱特征分析

水上溢油光谱作为高光谱遥感目标识别与分类的参考依据,在溢油识别与厚度区分等方面具有重要的研究意义。通过测量厚度范围为1.0～127 μm间的轻柴油的20组光谱曲线,计算其反射率光谱曲线随厚度变化的特征,并利用db4小波对反射率数据进行处理,突出光谱奇异性及其位置与奇异值随油膜厚度变化的特征。在研究范围内的油膜光谱反射率高于水体,但反射率值与油膜厚度间无固定增减关系。在其厚度小于6 μm时反射率光谱曲线无明显特征,厚度大于6 μm后在388 nm附近存在区别于水体的反射峰特征且随厚度增加特征愈加突出。油膜光谱小波分析后的细节系数在388～393 nm内表现出明显的奇异性,并且奇异位置随厚度增加向短波方向移动、奇异极值增大。研究证实了小波分析在确定油膜光谱特征位置与变化研究中的积极作用,并发现了紫外-可见光短波范围内的光谱特征,为紫外遥感进行溢油识别提供了科学依据。     

Thickness dependence of structural, electrical and optical properties of indium tin oxide (ITO) films deposited on PET substrates

Without intentionally heating the substrates, indium tin oxide (ITO) thin films of thicknesses from 72 nm to 447 nm were prepared on polyethylene terephthalate (PET) substrates by DC reactively magnetron sputtering with pre-deposition substrate surfaces plasma cleaning. The dependence of structural, electrical, and optical properties on the films thickness were systematically investigated. It was found that the crystal grain size increases, while the transmittance, the resistivity, and the sheet resistance decreases as the film thickness was increasing. The thickest film (∼447 nm) was found of the lowest sheet resistance 12.6 Ω/square, and its average optical transmittance (400-800 nm) and the 550 nm transmittance was 85.2% and 90.4%, respectively. The results indicate clearly that dependence of the structural, electrical, and optical properties of the films on the film thickness reflected the improvement of the film crystallinity with the film thickness.     

1 064 nm激光对氧化铟锡薄膜的损伤研究

 液晶光学器件在激光光束精密控制上具有重要应用前景,氧化铟锡（ITO）薄膜作为液晶光学器件的透明导电电极,是液晶器件激光损伤的薄弱环节。为此,建立了ITO薄膜激光热损伤物理模型。理论计算结果表明：1 064 nm激光对ITO薄膜的损伤主要为热应力损伤;连续激光辐照下,薄膜损伤始于靠近界面的玻璃基底内;脉冲激光辐照下,温升主要发生在光斑范围内的膜层,薄膜损伤从表面开始。利用泵浦探测技术,研究了ITO薄膜的损伤情况,测量了不同功率密度激光辐照后薄膜的方块电阻,结合1-on-1法测定了ITO薄膜的50%损伤几率阈值。实验结果表明：薄膜越厚,方块电阻越小,激光损伤阈值越低;薄膜未完全损伤前,方块电阻随激光功率密度的增加而增大。理论计算与实验结果吻合较好。设计液晶光学器件中的ITO薄膜电极厚度时,应综合考虑激光损伤、透光率及薄膜电阻的影响。     

Fabrication and characterization of Pt intermediate transparent and conducting ITO/Pt/ITO multilayer films

Platinum intermediate transparent and conducting ITO/metal/ITO (IMI) multilayered films were deposited by RF and DC magnetron sputtering on polycarbonate substrates without intentional substrate heating. Changes in the microstructure and optoelectrical properties of the films were investigated with respect to the thickness of the intermediate Pt layer in the IMI films. The thickness of Pt film was varied from 5 to 20 nm.In XRD measurements, neither ITO single-layer films nor IMI multilayer films showed any characteristic diffraction peaks for In₂O₃ or SnO₂. Only a weak diffraction peak for Pt (1 1 1) was obtained in the XRD spectra. Thus, it can be concluded that the Pt-intermediated films in the IMI films did not affect the crystallinity of the ITO films. However, equivalent resistivity was dependent on the presence and thickness of the Pt-intermediated layer. It decreased as low as 3.3×10⁻⁴ Ω cm for ITO 50 nm/Pt 20 nm/ITO 30 nm films. Optical transmittance was also strongly influenced by the Pt-intermediated layer. As Pt thickness in the IMI films increased, optical transmittance decreased to as low as 30% for ITO 50 nm/Pt 20 nm/ITO 30 nm films.     

Annealing induced refinement on optical transmission and electrical resistivity of indium tin oxide

The effect of annealing condition on sputtered indium tin oxide （ITO） films on quartz with the thickness of 200 nm is characterized to show enhanced optical transparency and optimized electrical contact resistivity. The as-deposited grown ITO film exhibits only 65% and 80% transmittance at 532 and 632.8 nm, respectively. After annealing at 475 ℃ for 15 min, the ITO film is refined to show improved transmittance at shorter wavelength region. The transmittances of 88.1% at 532 nm and 90.4% at 632.8 nm can be obtained. The 325-nm transmittance of the post-annealed ITO film is greatly increased from 12.7% to 41.9%. Optimized electrical property can be obtained when annealing below 450 ℃, leading to a minimum sheet resistance of 26 Ω/square. Such an ITO film with enhanced ultraviolet （UV） transmittance has become an alternative candidate for applications in current UV photonic devices. The morphology and conductance of the as-deposited and annealed ITO films are determined by using an atomic force microscopy （AFM）, showing a great change on the uniformity distribution with finite improvement on the surface conductance of the ITO film after annealing.     

Transparent conductive ITO/Ag/ITO multilayer electrodes deposited by sputtering at room temperature

ITO/Ag/ITO multilayers have been prepared onto conventional soda lime glass substrates by sputtering at room temperature. The optical and electrical characteristics of single layer and multilayer structures have been investigated as a function of the Ag and ITO film thicknesses. Transmittance and sheet resistance values are found mainly dependent on the Ag film thickness; whereas the wavelength range at which the maximum transmittance is achieved can be changed by adjusting the ITO films thickness. ITO/Ag/ITO electrodes with sheet resistance below 6 Ω/sq have been obtained for Ag film thickness above 10 nm and ITO layers thickness in the 30-50 nm range. These multilayers also show high transmittance in the visible spectral region, above 90% by discounting the glass substrate, with a maximum that is located at higher wavelengths for thicker ITO.     

Low temperature deposition of transparent conducting ITO/Au/ITO films by reactive magnetron sputtering

Transparent conducting indium tin oxide/Au/indium tin oxide (ITO) multilayered films were deposited on unheated polycarbonate substrates by magnetron sputtering. The thickness of the Au intermediated film varied from 5 to 20 nm. Changes in the microstructure, surface roughness and optoelectrical properties of the ITO/Au/ITO films were investigated with respect to the thickness of the Au intermediated layer. X-ray diffraction measurements of ITO single layer films did not show characteristic diffraction peaks, while ITO/Au/ITO films showed an In₂O₃ (2 2 2) characteristic diffraction peak. The optoelectrical properties of the films were also dependent on the presence and thickness of the Au thin film. The ITO 50 nm/Au 10 nm/ITO 40 nm films had a sheet resistance of 5.6 Ω/□ and an average optical transmittance of 72% in the visible wavelength range of 400-700 nm. Consequently, the crystallinity, which affects the optoelectrical properties of ITO films, can be enhanced with Au intermediated films.     

基于金属掺杂ITO透明导电层的紫外LED制备

为降低ITO薄膜对紫外波段的光吸收,制备低电压高功率的紫外LED,研究了一种基于金属掺杂ITO透明导电层的365 nm紫外LED的制备工艺。利用1 cm厚的石英片生长了不同厚度ITO薄膜以及在ITO上掺杂不同金属的新型薄膜,并研究了在不同的退火条件下这种薄膜的电阻和透过率,分析了掺杂金属ITO薄膜的带隙变化。将这种掺杂的ITO薄膜生长在365 nm外延片上并完成电极生长,制备成14 mil×28 mil的正装LED芯片。利用电致发光（EL）设备对LED光电性能进行测试并对比。实验结果表明:掺Al金属的ITO薄膜能够相对ITO薄膜的带隙提高0.15 eV。在600℃退火后,方块电阻降低6.2 Ω/□,透过率在356 nm处达到90.8%。在120 mA注入电流下,365 nm LED的电压降低0.3 V,功率提高14.7%。ITO薄膜掺金属能够影响薄膜带隙,改变紫光LED光电性能。     

Characteristic difference between ITO/ZrCu and ITO/Ag bi-layer films as transparent electrodes deposited on PET substrate

The metallic-glass film of ZrCu layer deposited by co-sputtering was utilized as the metallic layer in the bi-layer structure transparent conductive electrode of ITO/ZrCu (IZC) deposited on the PET substrate using magnetron sputtering at room temperature. In addition, the pure Ag metal layer was applied in the same structure of transparent conductive film, ITO/Ag, in comparison with the IZC film. The ZrCu layer could form a continuous and smooth film in thickness lower than 6 nm, compared with the island structure of pure Ag layer of the same thickness. The 30 nm ITO/3 nm ZrCu films could show the optical transmittance of 73% at 550 nm wavelength. The 30 nm ITO/12 nm ZrCu films could show the better sheet resistance of 20 Ω/sq, but it was still worse than that of the ITO/Ag films. It was suggested that an alloy system with lower resistivity and negative mixing heat between atoms might be another way to form a continuous layer in thickness lower than 6 nm for metal film.     

Plasma-based sputtering of indium tin oxide for the application of photovoltaic cells

Transparent and conducting indium tin oxide (ITO) thin films were deposited on soda lime glass substrates by RF plasma magnetron sputtering at room temperature. The effect of thickness (100, 200 and 300?nm) on the physical (structural, optical, electrical) properties of ITO thin films was investigated systematically. It is observed that with an increase in thickness, the X-ray diffraction data indicate polycrystalline films with grain orientations predominantly along (222) and (400) directions; the average grain size increases from 10 to 30?nm; the optical band gap increases from 3.68 to 3.73?eV and the transmission decrease from 80% to 70% . Four-point probes show a low resistivity (2.4×10^?5?Ω?cm) values for film with a thickness 300?nm. Present work shows that the ITO is a promising transparent conductive oxide material for the solar cell application.     

Characterization of dip-coated ITO films derived from nanoparticles synthesized by␣low-pressure spray pyrolysis

In₂O₃:Sn (Indium Tin Oxide; ITO) films were prepared from a sol solution with highly crystalline ITO nanoparticles (less than 20 nm in size with 10 at.% Sn) which had been prepared by low-pressure spray pyrolysis (LPSP) in a single step. The ITO sol solution was prepared by dispersing LPSP-prepared ITO nanoparticles into ultra pure water. The nanoparticle ITO film was deposited on a glass substrate using a dip-coating method and then annealed in air at various temperatures. The optical transmittances of the ITO films were measured by UV–Vis spectrometry, and the films were found to have a high transparency to visible light (in the case of a film thickness of 250 nm annealed at 400°C, the transparency was in excess of 95% over the range λ=450–800 nm, with a maximum value near 100% at wavelengths above λ=700 nm). The optical transmittances of the films were influenced by the size of the ITO particle used, the film thickness and the annealing temperature. The ITO films showed a minimum resistivity of 9.5×10⁻² Ω cm, and their resistivity was affected by both the ITO particle size and the annealing temperature used.     

ITO/Au/ITO multilayer thin films for transparent conducting electrode applications

Transparent and conducting ITO/Au/ITO multilayered films were deposited without intentional substrate heating on polycarbonate (PC) substrate using a magnetron sputtering process. The thickness of ITO, Au and ITO metal films in the multilayered structure was constant at 50, 10 and 40 nm, respectively.Although the substrate temperature was kept constant at 70 °C, ITO/Au/ITO films were polycrystalline with an (1 1 0) X-ray diffraction peak, while single ITO films were amorphous. Surface roughness analysis indicated ITO films had a higher average roughness of 1.76 nm, than the ITO/Au/ITO film roughness of 0.51 nm. The optoelectrical properties of the ITO/Au/ITO films were dependent on the Au thin film, which affected the ITO film crystallinity. ITO/Au/ITO films on PC substrates were developed with a resistivity as low as 5.6 × 10⁻⁵ Ω cm and a high optical transmittance of 71.7%.     

Rapid thermal annealing of ITO films

Tin-doped indium oxide (ITO) films with 200 nm thickness were deposited on glass substrates by DC magnetron sputtering at room temperature. And they were annealed by rapid thermal annealing (RTA) method in vacuum ambient at different temperature for 60 s. The effect of annealing temperature on the structural, electrical and optical properties of ITO films was investigated. As the RTA temperature increases, the resistivity of ITO films decreases dramatically, and the transmittance in the visible region increases obviously. The ITO film annealed at 600 °C by RTA in vacuum shows a resistivity of 1.6 × 10⁻⁴ Ω cm and a transmittance of 92%.     

银薄膜对光学基底表面粗糙度及光散射的影响

为了研究金属银薄膜与光学基底表面粗糙度和光散射的关系,提出了通过对光学薄膜矢量散射公式积分来获得界面粗糙度完全相关模型和完全非相关模型下其表面的总反射散射的方法.理论计算了光学基底上两种模型在不同厚度银膜下的总反射散射和双向反射分布函数.结果表明,当沉积在光学基底上的银薄膜的厚度大于80 nm后,两种模型下计算的银薄膜的表面总反射散射都等于基底的总积分散射,银薄膜能较好地复现出基底的粗糙度轮廓.实验研究表明为了复现基底的粗糙度,银薄膜的最佳厚度应在80~160 nm之间.     

Thermal stability of Ag films in air prepared by thermal evaporation

The thermal stability of silver films in air has been studied. Pure Ag films, 250 nm in thickness, were prepared on glass substrates by thermal evaporation process, and subsequently annealed in air for 1 h at temperatures between 200 and 400 °C. The structure and morphology of the samples were investigated by X-ray diffraction, Raman spectra and atomic force microscopy. It is found that the crystallization enhances for the annealed films, and film surface becomes oxidized when annealing temperature is higher than 350 °C. The electrical and optical properties of the films were studied by van der Pauw method and spectrophotometer, respectively. Reflectance drops sharply as Ag films are annealed at temperatures above 250 °C. Film annealed at 250 °C has the maximum surface roughness and the minimum reflectance at 600 nm optical wavelength. Film annealed at 200 °C has the minimum resistivity, and resistivity increases with the increasing of the annealing temperature when temperature is above 200 °C. The results show that both oxidization on film surface and agglomeration of silver film result in infinite of electrical resistivity as the annealing temperature is above 350 °C.     

Dependence of film thickness on the structural and optical properties of ZnO thin films

ZnO thin films are prepared on glass substrates by pulsed filtered cathodic vacuum arc deposition (PFCVAD) at room temperature. Optical parameters such as optical transmittance, reflectance, band tail, dielectric coefficient, refractive index, energy band gap have been studied, discussed and correlated to the changes with film thickness. Kramers-Kronig and dispersion relations were employed to determine the complex refractive index and dielectric constants using reflection data in the ultraviolet-visible-near infrared regions. Films with optical transmittance above 90% in the visible range were prepared at pressure of 6.5 × 10⁻⁴ Torr. XRD analysis revealed that all films had a strong ZnO (0 0 2) peak, indicating c-axis orientation. The crystal grain size increased from 14.97 nm to 22.53 nm as the film thickness increased from 139 nm to 427 nm, however no significant change was observed in interplanar distance and crystal lattice constant. Optical energy gap decreased from 3.21 eV to 3.19 eV with increasing the thickness. The transmission in UV region decreased with the increase of film thickness. The refractive index, Urbach tail and real part of complex dielectric constant decreased as the film thickness increased. Oscillator energy of as-deposited films increased from 3.49 eV to 4.78 eV as the thickness increased.     

基于低维相变薄膜的显示器件光学性质的研究

采用传输矩阵模型研究了基于低维相变薄膜的显示器件的光学特性与器件结构的关系。显示器件的类型有反射型和透射型,器件结构的关键参数包括Ge_2Sb_2Te_5(GST)层的厚度、ITO层的厚度、GST层的晶态与非晶态的变化。结果表明:对于反射型器件,ITO层的厚度对器件的反射光谱影响较大,可以通过改变ITO层的厚度达到改变器件颜色的效果;GST层的厚度为12 nm时,GST的晶态与非晶态的变化使器件有最好的颜色对比度且消耗较低的电功率。对于透射型器件,通过使用超薄的GST薄膜,器件的透明度可以保持很高,器件的透明度在GST的厚度超过几纳米后迅速下降。     

氧化铟锡薄膜的椭偏光谱研究

用溅射法在Si片上制备了厚度为140nm的氧化铟锡(ITO)薄膜。X射线衍射研究表明所制备的薄膜为多晶结构。在1.5~4.5eV范围内对ITO薄膜进行了椭偏测量。分别用德鲁德-洛伦茨谐振子(Drude Lorenz oscillators)模型、层进模型结合有效介质近似模型对椭偏参量ψ、Δ进行了拟合,得到ITO薄膜的折射指数n的变化范围在1.8~2.6之间,可见光范围内消光系数k接近于零,在350nm波长附近开始明显变化,且随着波长的减小k迅速增加。计算得到直接和间接光学带隙分别是3.8eV和4.2eV。并在1.5~4.5eV段给出一套较为可靠的、具有实用价值的ITO介电常量和光学常量。