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。     

不同衬底和CdCl2退火对磁控溅射CdS薄膜性能的影响

在科宁7059玻璃, FTO, ITO, AZO四种衬底上磁控溅射CdS薄膜, 并在CdCl₂+干燥空气380 ℃退火, 分别研究了不同衬底和退火工艺对CdS薄膜形貌、结构和光学性能的影响. 扫描电子显微镜形貌表明: 不同衬底原位溅射CdS薄膜的形貌不同, 退火后相应CdS薄膜的晶粒度和表面粗糙度明显增大. XRD衍射图谱表明: 不同衬底原位溅射和退火CdS薄膜均为六角相和立方相的混相结构, 退火前后科宁7059玻璃, FTO, AZO衬底上CdS薄膜有 H(002)/C(111) 最强衍射峰, ITO衬底原位溅射CdS薄膜没有明显的最强衍射峰, 退火后出现 H(002)/(111) 最强衍射峰. 紫外-可见分光光度计分析表明: AZO, FTO, ITO, 科宁7059玻璃衬底CdS薄膜的可见光平均透过率依次减小, 退火后相应衬底CdS薄膜的可见光平均透过率增大, 光学吸收系数降低; 退火显著增大了不同衬底CdS薄膜的光学带隙. 分析得出: 上述结果是由于不同衬底类型和退火工艺对CdS多晶薄膜的形貌、结构和带尾态掺杂浓度改变的结果. 关键词： CdS薄膜 磁控溅射 退火再结晶 带尾态     

退火温度对旋涂法制备SnO_2薄膜性能的影响

采用旋涂法在玻璃基底上制备SnO_2薄膜,通过原子力显微镜(AFM)、X射线反射(XRR)、傅氏转换红外线光谱仪(FT-IR)、X射线衍射(XRD)、紫外-可见分光光度计、四探针、开尔文探针系统对薄膜的表面形貌、结构及光学特性、电学特性进行分析,探讨了退火温度对薄膜质量的影响及作用机制。研究发现:随着退火温度升高,薄膜厚度和有机成分杂质减小,薄膜密度递增,但薄膜表面粗糙度有所上升;当退火温度升高至500℃时,薄膜结构由非晶转变为结晶,其主要晶面为氧化锡的(110)、(101)和(211)晶面。旋涂法制备的氧化锡薄膜在可见光区域的平均透光率在90%以上,随着退火温度上升,薄膜在400～800 nm波段的透光率先减小后增大,薄膜的带隙宽度分别为3. 840 eV(沉积态薄膜)、3. 792 eV(100℃)、3. 690 eV(300℃)和3. 768eV(500℃);薄膜的电导率也随着退火温度升高而增加,在500℃时电导率高达916 S/m;薄膜的功函数先增大后减小,分别为(4. 61±0. 005) eV(沉积态薄膜)、(4. 64±0. 005) eV(100℃)、(4. 82±0. 025) eV(300℃)、(4. 78±0. 065) eV(500℃)。     

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%.     

Effect of thickness on physical properties of electron beam vacuum evaporated CdZnTe thin films for tandem solar cells

The thickness and physical properties of electron beam vacuum evaporated CdZnTe thin films have been optimized in the present work. The films of thickness 300 nm and 400 nm were deposited on ITO coated glass substrates and subjected to different characterization tools like X-ray diffraction (XRD), UV‐Vis spectrophotometer, source meter and scanning electron microscopy (SEM) to investigate the structural, optical, electrical and surface morphological properties respectively. The XRD results show that the as-deposited CdZnTe thin films have zinc blende cubic structure and polycrystalline in nature with preferred orientation (111). Different structural parameters are also evaluated and discussed. The optical study reveals that the optical transition is found to be direct and energy band gap is decreased for higher thickness. The transmittance is found to increase with thickness and red shift observed which is suitable for CdZnTe films as an absorber layer in tandem solar cells. The current-voltage characteristics of deposited films show linear behavior in both forward and reverse directions as well as the conductivity is increased for higher film thickness. The SEM studies show that the as-deposited CdZnTe thin films are found to be homogeneous, uniform, small circle-shaped grains and free from crystal defects. The experimental results confirm that the film thickness plays an important role to optimize the physical properties of CdZnTe thin films for tandem solar cell applications as an absorber layer.     

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.     

Preparation and characterization of nanocrystalline ITO thin films on glass and clay substrates by ion-beam sputter deposition method

Nanocrystalline indium tin oxide (ITO) thin films were prepared on clay-1 (Clay-TPP-LP-SA), clay-2 (Clay-TPP-SA) and glass substrates using ion-beam sputter deposition method. X-ray diffraction (XRD) patterns showed that the as-deposited ITO films on both clay-1 and clay-2 substrates were a mixture of amorphous and polycrystalline. But the as-deposited ITO films on glass substrates were polycrystalline. The surface morphologies of as-deposited ITO/glass has smooth surface; in contrast, ITO/clay-1 has rough surface. The surface roughnesses of ITO thin films on glass and clay-1 substrate were calculated as 4.3 and 83 nm, respectively. From the AFM and SEM analyses, the particle sizes of nanocrystalline ITO for a film thickness of 712 nm were calculated as 19.5 and 20 nm, respectively. Optical study showed that the optical transmittance of ITO/clay-2 was higher than that of ITO/clay-1. The sheet resistances of as-deposited ITO/clay-1 and ITO/clay-2 were calculated as 76.0 and 63.0 Ω/□, respectively. The figure of merit value for as-deposited ITO/clay-2 (12.70 × 10⁻³/Ω) was also higher than that of ITO/clay-1 (9.6 × 10⁻³/Ω), respectively. The flexibilities of ITO/clay-1 and ITO/clay-2 were evaluated as 13 and 12 mm, respectively. However, the ITO-coated clay-2 substrate showed much better optical and electrical properties as well as flexibility as compared to clay-1.     

The electrical, optical properties of AlSb polycrystalline thin films deposited by magnetron co-sputtering without annealing

In order to fabricate AlSb polycrystalline thin films without post annealing, this paper studies a technology of magnetron co-sputtering onto intentionally heated substrate. It compares the structural characteristics and electrical properties of AlSb films which are deposited at different substrate temperatures. It finds that the films prepared at a substrate temperature of 450 oC exhibit an enhanced grain growth with an average grain size of 21 nm and the lattice constant is 0.61562 nm that goes well with unstained lattice constant (0.61355 nm). The ln(σ_dark) ～1/T curves show that the conductivity activation energy is about 0.38 eV when the film is deposited at 450 oC without an annealing. The transmittance and reflectance spectra show that the film deposited at 450 oC has an optical band gap of 1.6 eV. These results indicate that we have prepared AlSb polycrystalline films which do not need a post annealing.     

中频孪生磁控溅射WO3薄膜及变色性能研究

采用先进的中频孪生非平衡磁控溅射技术,以金属钨为靶材,制备非晶态WO3电致变色薄膜。用X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外分光光度计等测试手段分析薄膜的结构、表面形貌、成分以及透射光谱特性。研究了氧气流量比及热处理温度对WO3薄膜变色性能的影响。结果表明,中频孪生非平衡磁控溅射技术是制备WO3变色薄膜的一种有效方法;室温条件下沉积获得的原始态薄膜为非晶态WO3;提高氧气流量比和适当热处理温度能有效改善薄膜的电致变色性能。实验中在较高氧气流量比,200℃热处理条件下制备的薄膜在380~780 nm的可见光范围内着色态和褪色态平均透光率差值高达50%以上,表现出较好的电致变色性能。     

Pulsed laser deposition of tantalum pentoxide film

We report thin tantalum pentoxide (Ta₂O₅) films grown on quartz and silicon substrates by the pulsed laser deposition (PLD) technique employing a Nd:YAG laser (wavelength 5=532 nm) in various O₂ gas environments. The effect of oxygen pressure, substrate temperature, and annealing under UV irradiation using a 172-nm excimer lamp on the properties of the grown films has been studied. The optical properties determined by UV spectrophotometry were also found to be a sensitive function of oxygen pressure in the chamber. At an O₂ pressure of 0.2 mbar and deposition temperatures between 400 and 500 °C, the refractive index of the films was around 2.18 which is very close to the bulk Ta₂O₅ value of 2.2, and an optical transmittance around 90% in the visible region of the spectrum was obtained. X-ray diffraction measurements showed that the as-deposited films were amorphous at temperatures below 500 °C and possessed an orthorhombic (#-Ta₂O₅) crystal structure at temperatures above 600 °C. The most significant result of the present study was that oxygen pressure could be used to control the composition and modulate optical band gap of the films. It was also found that UV annealing can significantly improve the optical and electrical properties of the films deposited at low oxygen pressures (<0.1 mbar).     

Au层退火温度对ZnO/Au/ZnO多层膜的结构、光学及电学性质的影响

采用金属有机化学气相沉积(MOCVD)技术在蓝宝石衬底上制备出晶体质量较好的透明导电的ZnO/Au/ZnO(ZAZ)多层膜,其中,Au夹层是通过射频磁控溅射的方法获得。通过对Au夹层进行不同温度的退火处理,研究了Au层退火温度对ZAZ多层膜的结构特性、电学性能和光学特性的影响。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射(XRD)仪、霍尔效应测试和透射谱分析等测试手段对ZAZ多层膜的性质进行了分析。测试结果表明,在200 ℃下对Au夹层进行快速退火处理,多层膜的结构、电学和光学性质达到最优,表面等离子体效应也更明显。其中,XRD(002)衍射峰的半高宽为0.14°,电阻率为2.7×10^-3 Ω·cm,载流子浓度为1.07×10²⁰ cm^-3,可见光区平均透过率为75.3%。     

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.     

热处理温度对ZnO∶Al薄膜性能的影响

利用溶胶-凝胶技术在玻璃衬底上制备了ZnO∶Al薄膜,表征了薄膜的结构、光透过和光致发光特性,探讨了热处理温度对薄膜晶体结构和光学性质的影响.结果表明,在热分解温度400 ℃和退火温度600 ℃时,ZnO∶Al薄膜的C轴择优取向明显,透过率较高.在热处理温度400 ℃情况下,激发波长340 nm的光致发光谱中有三个发光中心,紫外发光强度随退火温度的升高先升高后下降,500 ℃时发光强度最强.其它两个发光峰的强度随退火温度的升高而降低甚至消失.激发波长不同,ZnO∶Al薄膜的发光中心和强度均发生变化.     

铟锡氧化物薄膜表面等离子体损耗降低的研究

本文采用直流磁控溅射方法在普通浮法玻璃基底上制备了立方多晶铁锰矿结构的铟锡氧化物(indium tin oxide, ITO)薄膜,并对其进行了结晶性、表面粗糙度、紫外-可见吸收光谱、折射率、介电常数及霍尔效应的测试.研究了溅射时基底温度的改变对于ITO薄膜的光电、表面等离子体性质的影响.随着基底温度由100?C升高至500?C,其光学带隙(3.64—3.97eV)展宽,减少了电子带间跃迁的概率,有效降低了ITO薄膜的光学损耗.与此同时,对应ITO薄膜的载流子浓度(4.1×10~(20)-—2.48×10~(21)cm~(-3))与迁移率(24.6—32.2 cm~2·V~(-1)·s~(-1))得到提高,电学损耗明显降低.     

A simplified reactive thermal evaporation method for indium tin oxide electrodes

Indium tin oxide (ITO) films approximately 120 nm thick were deposited onto unheated glass substrates by using reactive thermal evaporation (RTE) and in situ post-evaporation annealing in oxygen. We show that this simplified method can be used to produce high quality ITO thin films with low electrical resistivity (10⁻³ Ω cm) and high transmittance (approximately 80% at 550 nm). The refractive index is approximately 2.0 and the direct optical band gap of the films (above 3.0 eV) is in good agreement with previously reported values. Since this deposition method does not require heating the substrates or furnace annealing at high temperatures, it can be advantageous when it is necessary to decrease the thermal budget on underlying devices or layers.     

The effects of post-thermal annealing on the optical parameters of indium-doped ZnO thin films

Indium-doped ZnO thin films are deposited on quartz glass slides by RF magnetron sputtering at ambient temper- ature. The as-deposited films are annealed at different temperatures from 400 C to 800 C in air for 1 h. Transmittance spectra are used to determine the optical parameters and the thicknesses of the films before and after annealing using a nonlinear programming method, and the effects of the annealing temperatures on the optical parameters and the thickness are investigated. The optical band gap is determined from the absorption coefficient. The calculated results show that the film thickness and optical parameters both increase first and then decrease with increasing annealing temperature from 400 C to 800 C. The band gap of the as-deposited ZnO:In thin film is 3.28 eV, and it decreases to 3.17 eV after annealing at 400 C. Then the band gap increases from 3.17 eV to 3.23 eV with increasing annealing temperature from 400 C to 800 C.     

低压反应离子镀方法制备ITO透明导电膜

溅射镀膜方法是制备ITO透明导电膜最常用也是实验研究最多的方法。实验使用一种不同于溅射方法的另一种制备工艺—低压反应离子镀方法—制备ITO透明导电膜。实验对不同沉积速率和不同氧气流量对ITO透明导电膜的方块电阻以及光学透过率的影响进行了详细地分析,并综合比较得到了当沉积速率为0.5nm/s,氧气流量为24cm3/min时,在波长为550nm处,方块电阻为20Ω,λ=550nm透过率为90.8%的优质ITO透明导电膜。     

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.     

纳米ZnO-SiO2自清洁增透薄膜的制备及其性能

以乙酸锌醇热法ZnO纳米粒子为基料, 通过溶胶-凝胶浸渍提拉法制备纳米ZnO-SiO₂自清洁增透薄膜. 采用透射电镜, 光谱椭偏仪, 扫描电镜, X-射线衍射, 差热分析仪和UV-vis等技术对样品进行表征, 以亚甲基蓝的光催化降解为目标反应, 评价其光催化活性. 结果表明, ZnO纳米粒子为球粒状结构, 直径约12-20 nm, 特征紫外吸收波长位于375 nm 处; 与未涂覆纳米ZnO-SiO₂自清洁增透薄膜的石英玻璃基底相比, 涂覆后石英玻璃在400-800 nm波长范围内平均透光率提升达4.17%, 具有良好的宽光谱增透行为; 且在紫外光激发下对亚甲基蓝染料具有光催化降解特性, 进而具备良好的自清洁性能.     

Electrical and optical properties of indium tin oxide thin films grown by pulsed laser deposition

Indium tin oxide (ITO) thin films (200-400 nm in thickness) have been grown by pulsed laser deposition (PLD) on glass substrates without a post-deposition anneal. The electrical and optical properties of these films have been investigated as a function of substrate temperature and oxygen partial pressure during deposition. Films were deposited at substrate temperatures ranging from room temperature to 300 °C in O₂ partial pressures ranging from 0.1 to 100 mTorr. For 300 nm thick ITO films grown at room temperature in oxygen pressure of 10 mTorr, the electrical conductivity was 2.6᎒^-3 Q^-1cm^-1 and the average optical transmittance was 83% in the visible range (400-700 nm). For 300 nm thick ITO films deposited at 300 °C in 10 mTorr of oxygen, the conductivity was 5.2᎒^-3 Q^-1cm^-1 and the average transmittance in the visible range was 87%. Atomic force microscopy (AFM) measurements showed that the RMS surface roughness for the ITO films grown at room temperature was ~7 Å, which is the lowest reported value for the ITO films grown by any film growth technique at room temperature.