氧化物半导体透明导电薄膜的最佳掺杂含量理论计算

以铝掺杂氧化锌(A1-doped ZnO,简称AZO)和锡掺杂氧化铟(Sn-dopedIn2O3,简称ITO)薄膜为例,建立了一个氧化物半导体透明导电薄膜的最佳掺杂含量的理论表达式,定量计算的结果AZO陶瓷靶材中铝含量的理论最佳值为C≈2.9894%(wt),ITO陶瓷靶材中锡含量的理论最佳值为C≈10.3114%(wt),与实验数据相符合.该理论经适当的修改和解释后也适用于某些其他电子薄膜材料的最佳掺杂含量问题.     

基底温度对直流磁控溅射ITO透明导电薄膜性能的影响

用直流磁控溅射法制备透明导电锡掺杂氧化铟(ITO)薄膜,靶材为ITO陶瓷靶,组分为m(In2O3):m(SnO2)=9:1.运用分光光度计,四探针测试仪研究了基底温度对薄膜透过率、电阻率的影响,并用X射线衍射(XRD)仪对薄膜进行结构分析.计算了晶面间距和晶粒尺寸,分析了薄膜的力学性质.实验结果表明,在实验设备条件下,直流磁控溅射ITO陶瓷靶制备ITO薄膜时,适当的基底温度(200℃)能在保证薄膜85%以上高可见光透过率下,获得最低的电阻率,即基底温度有个最佳值.薄膜的结晶度随着基底温度的提高而提高.     

In_2O_3∶Sn和ZnO∶Al透明导电薄膜的结构及其导电机制

基于对锡掺杂三氧化铟 ( Sn- doped In2 O3,简称 ITO)和铝掺杂氧化锌 ( Al- doped Zn O,简称 ZAO)薄膜退火前后 XRD数据的分析 ,研究了薄膜晶格常数畸变的原因 ,同时讨论了 ITO和ZAO薄膜的导电机制 .结果表明 ,低温沉积 ITO薄膜的晶格膨胀来源于 Sn2 +对 In3-的替换 ,导电电子则由氧缺位提供 ;高温在位制备和退火处理后薄膜的晶格收缩来源于 Sn4 + 对 In3+ 的替换 ,导电电子则主要由 Sn4 + 取代 In3+ 后提供 .低温 ZAO薄膜的晶格畸变来源于薄膜中的残余应力 ,导电电子的来源则同高温在位和退火处理后的薄膜一致 ,即由 Al3+ 对 Zn2 + 的替换和氧缺位两者     

SnO2的含量对ITO透明导电薄膜结构和光电特性的影响

阐述了射频磁控溅射方法制备的柔性衬底ITO透明导电膜的结构和光电特性与靶材中SnO2含量的关系.ITO靶材中In2O3掺杂SnO2最佳比例(质量比)为7.5%,制备薄膜的霍耳迁移率为89.3 cm2/(V·s),电阻率为6.3×10-4Ω·cm,在可见光范围内相对透过率为85%左右,随着靶材中SnO2含量增大,薄膜的光学带隙展宽.用不同掺杂比例的靶材制备的薄膜均为多晶纤锌矿结构,掺杂比例增大,样品的晶格常数变大,晶格畸变明显.     

退火温度对AZO薄膜场发射性能的影响

以纯度为99.95%、Al2O3为2wt.%的ZnO-Al2O3金属氧化物为溅射靶材,采用射频(RF)磁控溅射的方法,在玻璃衬底上制备Al掺杂ZnO(AZO)薄膜,研究其场发射特性和导电性能,并分析了不同的退火温度对AZO薄膜的形貌、导电及场发射性能的影响。采用原子力显微镜(AFM)及X射线衍射(XRD)对AZO薄膜表面形貌与结晶特性进行测试的结果表明,随着退火温度的升高,AZO薄膜的表面粗糙度随之增大,AZO薄膜的结晶度变好;场发射性能研究的结果表明,AZO薄膜的开启电场随着退火温度增加呈先减小后增大的趋势,当退火温度为300℃时,AZO薄膜样品粗糙度最大,场发射性能最好,开启场强为2.8V/μm,发光均匀性较好,亮度达到650cd/m2,导电性能最好,电阻率为5.42×10-4Ω·cm。     

衬底温度对Al2O3掺杂ZnO透明导电薄膜性能的影响

以纯度为99.9％的陶瓷靶(w(ZnO)=98％,w(Al2O3)=2％)为溅射靶材,采用射频磁控溅射法在玻璃衬底上沉积制备了Al2O3掺杂的ZnO(AZO)薄膜.采用X射线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外可见光谱(UV-Vis)仪等仪器,对AZO薄膜的形貌结构、光电学性能进行了测试,从薄膜生长方式和缺...     

掺铝氧化锌陶瓷靶材的制备及其薄膜的光学性能

以Al(NO3)3.9H2O和ZnO粉体为原料,采用常压烧结方法制备了高致密度和高导电性的ZnO:Al(AZO)陶瓷靶材。研究了烧结温度对AZO靶材微观结构、相对密度和电性能的影响。当Al和Zn的摩尔比为3:100,烧结温度为1 400℃时,所制AZO靶材的致密度达96%,电阻率为2.5×10–2.cm。以烧结温度为1400℃的AZO陶瓷靶为靶材并通过直流磁控溅射在玻璃基片上制备出了高度c轴择优取向的AZO薄膜,其可见光透过率为90%,禁带宽度为3.63 eV,电阻率为1.7×10–3.cm。     

In2O3：Sn和ZnO：Al透明导电薄膜的结构及其导电机制

基于对锡掺杂三氧化铟(Sn-doped In2O3,简称ITO)和铝掺杂氧化锌(Al-doped ZnO,简称ZAO)薄膜退火前后XRD数据的分析,研究了薄膜晶格常数畸变的原因,同时讨论了ITO和ZAO薄膜的导电机制.结果表明,低温沉积ITO薄膜的晶格膨胀来源于Sn2+对In3-的替换,导电电子则由氧缺位提供;高温在位制备和退火处理后薄膜的晶格收缩来源于Sn4+对In3+的替换,导电电子则主要由Sn4+取代In3+后提供.低温ZAO薄膜的晶格畸变来源于薄膜中的残余应力,导电电子的来源则同高温在位和退火处理后的薄膜一致,即由Al3+对Zn2+的替换和氧缺位两者共同提供     

ZnO和Al2O3缓冲层对AZO透明导电膜薄膜性能的影响

采用射频磁控溅射法,以纯度为99.9%,质量分数98%ZnO、2%Al2O3陶瓷靶为溅射靶材,在预先沉积了ZnO和Al2O3的玻璃衬底上制备了Al2O3掺杂的ZnO薄膜。研究并对比了两种不同的缓冲层对ZnO∶Al(AZO)薄膜的微观结构和光电性能的影响。并借助X线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外可见光谱仪(UV-Vis)等方法测试和分析了不同缓冲层,对AZO薄膜的形貌结构、光电学性能的影响。结果表明:加入缓冲层后,在衬底温度为200℃时,溅射30min,负偏压为60V、在氮气气氛下经300℃退火处理后,制得薄膜的可见光透过率为83%～87%,AZO薄膜的最低电阻率,从9.2×10-4Ω.cm(玻璃)分别下降到8.0×10-4Ω.cm(ZnO)和5.4×10-4Ω.cm(Al2O3)。     

靶基距对磁控溅射AZO薄膜性能的影响

以氧化锌铝陶瓷靶(98%ZnO+2%Al2O3,质量分数)为靶材,利用直流磁控溅射法在载玻片衬底上制备了AZO(ZnO:Al)薄膜样品,研究了靶基距(40~70 mm)对所制备AZO薄膜微观结构及光电性能的影响。结果表明:不同靶基距下制备的薄膜均具有明显的c轴择优取向;随着靶基距的增加,所制AZO薄膜的结晶质量变好,结晶尺寸变大,电阻率降低,禁带宽度变小,且所有薄膜在可见光区的平均透过率均在80%以上。当靶基距为70 mm时所制AZO薄膜的性能最好,其电阻率为8×10–4?·cm,在可见光范围内的平均透过率为82.3%,禁带宽度为3.42 eV。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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