多功能电子信息材料MoS2的制备及其催化性能研究

半导体材料作为电子信息材料的一种，因具有较宽的禁带宽度和高的载流子迁移率成为了人们关注的热点材料之一。通过水热法制备了不同质量分数Ag掺杂(0,1%,3%,5%,7%)的MoS₂复合材料，采用XRD、SEM、UV-Vis、FT-IR、Raman和催化性能分析等手段对Ag掺杂MoS₂复合材料的晶体结构、微观形貌、光谱性能和催化性能进行了测试与表征。结果表明，水热法合成了单一相的六方晶系MoS₂,Ag成功掺杂到了MoS₂中。Ag掺杂的MoS₂复合材料为纳米片堆积形成的圆球状结构，Ag掺杂增大了MoS₂纳米球的直径，尺寸在300～350 nm之间。Ag的掺杂诱导了MoS₂的晶型从2H-MoS₂相结构向1T-MoS₂相结构转变，1T-MoS₂相结构的晶型含量增加。MoS₂复合材料对于可见光和紫外光的吸收能力增强，5%(质量分数)Ag掺杂的MoS_2...     

碳掺杂TiO2纳米管电极的简易制备及其光电化学性能

通过阳极氧化方法制备了TiO₂纳米管薄膜, 在NaHCO₃存在下对该薄膜进行热处理得到碳掺杂TiO₂(C-TiO₂)纳米管薄膜, 通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱、电化学阻抗谱(EIS)和Mott-Schottky等方法对得到的薄膜进行表征。XRD结果表明C-TiO₂纳米管薄膜中的TiO₂主要为锐钛矿晶型; SEM结果显示薄膜存在纳米管结构; XPS分析表明C-TiO₂纳米管薄膜中的C以替代型掺杂形式进入到TiO₂晶格中; 光电化学性能测试显示, 相对于TiO₂纳米薄膜, C-TiO₂阻抗减小, 平带电位由-0.28 V负移至-0.38 V, 具有更好的紫外-可见光和可见光响应, 紫外-可见光下的光电流是未掺杂的1.7倍。利用阳极氧化的Ti丝作为光阳极和Pt丝作为对电极组装了染料敏化太阳能电池并进行了性能测试, 结果表明, 经过碳掺杂的Ti /TiO₂丝为光阳极电池的短路电流密度和电池效率分别达到0.17 mA/cm²和3.8%, 较未掺杂的Ti/TiO₂丝为光阳极的电池的短路电流密度和电池效率均增大, 表明适量的碳掺杂有利于提高电池效率。     

单靶磁控溅射制备铜铟硒和铜铟锌硒薄膜及其结构、光学性质研究

采用单靶磁控溅射法制备了铜铟硒(CIS)和铜铟锌硒(CIZS)薄膜。XRD表征发现CIZS-300出现了与其它薄膜不同的择优取向, 分析认为贫铜的状态和适宜温度可能促使薄膜择优取向从(112)向(220)转化; 拉曼光谱在171 cm^-1处出现的较强峰, 和206 cm^-1处出现的较弱峰, 分别为A₁和B₂振动模式, 而Zn的掺入导致A₁拉曼峰的宽化和蓝移; Zn的掺入使Cu含量改变进而使CIZS禁带宽度增大, 这是由于Se的p轨道和Cu的d轨道杂化引起的; SEM测试结果表明CIZS薄膜表面比CIS表面更为紧密、平滑。     

由原子薄横向异质结构建的可调谐肖特基二极管（英文）

本研究利用一步化学气相沉积技术制备了Sn_xMo_1-xS₂/MoS₂横向异质结高性能二极管.通过选择性掺杂Sn原子到单层MoS₂的边缘,形成了与MoS₂相同晶格常数的Sn_xMo_1-xS₂.在边缘的Sn_xMo_1-xS₂和内部的MoS₂上分别沉积铬/金电极,形成肖特基势垒,其中势垒高度不同导致载流子仅在一个方向上传输.通过控制掺杂浓度和栅极电压,可实现MoS₂和Sn_xMo_1-xS₂之间费米能级的对齐调节,实现了可调整的整流比,最高达到10⁴.令人印象深刻的是,该二极管还表现出优异的光伏特性,该器件在λ=400 nm处实现了40%的外量子效率值.此外,我们在无外部偏压条件下实现了自供电光电探测,该异质结二...     

硅异质结太阳能电池用透明导电氧化物薄膜的研究现状及发展趋势

硅异质结(SHJ)太阳能电池是目前光伏产业中的重要组成部分,其由于具有高开路电压(V_oc)等优点而引起了广泛的关注。在硅异质结太阳能电池中,透明导电氧化物(TCO)薄膜层的光学性能和电学性能分别影响着电池的短路电流(J_sc)、填充因子(FF),进而影响电池的转换效率。近年来,SHJ电池中TCO层的研究主要集中于掺杂的In₂O₃和ZnO体系。本文从硅异质结太阳能电池的不同结构出发,概述了TCO薄膜的光电性能(透过率、禁带宽度、方块电阻、载流子浓度、迁移率和功函数)以及与相邻层的接触对电池性能的影响,介绍了不同体系的透明导电氧化物薄膜在硅异质结太阳能电池中的应用及研究现状,并展望其未来的发展趋势。     

Enhanced photoresponse of Ti02/MoS2heterostructure phototransistors by the coupling of interface charge transfer and photogating

Two-dimensional(2D)MoS₂with appealing physical properties is a promising candidate for next-generation electronic and optoelectronic devices,where the ultrathin MoS₂is usually laid on or gated by a dielectric oxide layer.The oxide/MoS₂interfaces widely existing in these devices have significant impacts on the carrier transport of the MoS₂channel by diverse interface interactions.Artificial design of the oxide/MoS₂interfaces would provide an effective way to break through the performance limit of the 2D devices but has yet been well explored.Here,we report a high-performance MoS₂-based phototransistor with an enhanced photoresponse by interfacing few-layer MoS₂with an ultrathin Ti0₂layer.The Ti0₂is deposited on MoS₂through the oxidation of an e-beam-evaporated ultrathin Ti layer.Upon a visible-light illumination,the fabricated Ti0₂/MoS₂phototransistor exhibits a responsivity of up to 2,199 A/W at a gate voltage of 60 V and a detectivity of up to 1.67×10¹³Jones at a zero-gate voltage under a power density of 23.2μW/mm².These values are 4.0 and 4.2 times those of the pure MoS₂phototransistor.The significantly enhanced photoresponse of Ti0₂/MoS₂device can be attributed to both interface charge transfer and photogating effects.Our results not only provide valuable insights into the interactions at Ti0₂/MoS₂interface,but also may inspire new approach to develop other novel optoelectronic devices based on 2D layered materials.     

高纵横比单层MoS2纳米-微米带的可控合成及其在高性能光电晶体管中的应用(英文)

本文报道了一种快速、可控合成单层MoS₂纳米-微米带的方法:通过在蓝宝石衬底上旋涂Na₂MoO₄和NaOH的混合溶液后一步化学气相沉积硫化的方式进行生长.其中,通过改变NaOH的浓度,对气-液-固生长过程中的反应物液滴流动性进行调控,我们实现了对所获得的MoS₂的形貌和取向的调控;同时,通过改变生长时间,可以实现对MoS₂层数的调控.利用这种方法,我们获得了最窄宽度仅为200 nm,纵横比超过100的单层MoS₂纳米-微米带,且表征证明其具有很高的晶体质量.同时,我们还用该MoS₂纳米带作为沟道材料,制备了光电晶体管,测试表明其具有高达9×10⁵的电流开/关比、超过10⁵的光暗电流比以及高达8.6 A W^-1的响应度,展现了其在电子和光电子器件中的应用潜力.     

基于MoS2/SiO2范德华异质结的VO2薄膜转移打印研究

近年来, 柔性电子器件由于在物联网、生物电子等领域的潜在应用引起了研究者的广泛关注。功能氧化物材料在柔性聚合物中的集成已被证明是实现高性能柔性电子器件的有效方式。由于功能氧化物薄膜通常需要高温制备, 直接在柔性聚合物基底上合成高质量的氧化物薄膜仍然是一个巨大的挑战。本研究提出了一种基于MoS₂/SiO₂范德华异质结转移打印大面积VO₂薄膜的方法, 即利用MoS₂和SiO₂薄膜亲疏水性能的不同, 可以仅使用去离子水解离MoS₂/SiO₂范德华异质结界面, 成功将Si/SiO₂/MoS₂/SiO₂/VO₂ 多层膜结构上的VO₂薄膜转印到Si、SiO₂/Si以及柔性基底上。X射线衍射(XRD)结果显示, 转印前后VO₂薄膜的晶体结构没有差异, 变温Raman光谱和变温红外反射光谱证明了转印前后VO₂薄膜良好的金属-绝缘体转变性能。本研究提供了一种有效的功能氧化物薄膜转印方法, 在不引入牺牲层和腐蚀性溶剂的条件下, 实现了VO₂薄膜在任意基底上的低温集成, 为柔性可穿戴电子器件的研制提供了一种新思路。     

典型低轨辐照环境对MoS2-Ti薄膜真空摩擦学性能的影响

采用非平衡磁控溅射方法在9Cr18基底上制备了MoS₂-Ti薄膜，并对4组样品分别进行了电子辐照、电子/质子辐照、电子/质子/紫外辐照、电子/质子/紫外/原子氧辐照。采用SEM、XRD、XPS分析了辐照前后薄膜的结构和化学组成变化，通过摩擦试验考察了辐照前后薄膜的摩擦学性能，探讨了其损伤机制。研究结果表明，电子辐照、质子辐照、紫外辐照对MoS₂-Ti薄膜的显微组织结构、表面形貌及摩擦学性能没有明显影响。动能5 eV的原子氧对MoS₂-Ti薄膜表面有显著的损伤，主要表现在表面出现“绒毯”状形态，Mo、S和Ti元素被氧化成高价氧化物。原子氧辐照导致MoS₂-Ti薄膜摩擦起始和中段摩擦因数升高、中段摩擦因数不稳定，比磨损率增大。     

Ti-Al共掺杂Si薄膜的光电性能增强机理研究

Ti超掺杂Si(Si:Ti)薄膜是通过脉冲激光的非平衡作用，在Si中掺入超固溶度3个数量级以上的高浓度Ti杂质形成。它摆脱了Si禁带宽度的限制，具有优异的亚带隙近红外(λ=1 100～2 500 nm)光吸收性能。通过真空电子束蒸发结合紫外纳秒激光熔融的方式，制备了Ti-Al共掺杂Si(Si:(Ti-Al))薄膜，以进一步提高薄膜的亚带隙近红外光吸收性能，更好地满足近红外器件的需求。研究结果表明，Si:(Ti-Al)薄膜的薄层电阻，由本征单晶Si衬底的10⁴Ω/square量级降低至10²Ω/square量级，与Si:Ti薄膜一致。但是，Si:(Ti-Al)薄膜在亚带隙近红外波段的吸光度，较本征单晶Si衬底平均提高了7倍，最大提高了一个数量级(λ=1 800 nm处);较Si:Ti薄膜平均提高了33%,最大提高了57.2%(λ=1 200 nm处)。表面形貌分析表明，Si:(Ti-Al)薄膜的二次激光加工降低了表面光反射。薄膜成分分析表明，Si:(Ti-Al)薄膜中存在TiSi₂和AlTi。TiSi₂     

基体表面粗糙度对MoS_(2)/Ti薄膜摩擦磨损性能的影响EI北大核心CSCD

为揭示基体表面粗糙度对MoS_(2)/Ti固体润滑薄膜摩擦磨损性能的影响规律,并探究其摩擦磨损机理,采用磁控溅射方法,在不同表面粗糙度的轴承钢基体上沉积MoS_(2)/Ti薄膜。通过划痕测试仪、X射线衍射仪、场发射扫描电子显微镜和粗糙度轮廓仪,分别评价MoS_(2)/Ti薄膜的膜基结合力、物相成分、表面微观形貌以及表面粗糙度,并采用球-盘摩擦磨损实验研究干摩擦、固体-油复合润滑和固体-脂复合润滑条件下,MoS_(2)/Ti薄膜的摩擦磨损性能。结果表明:随着基体表面粗糙度的增加,MoS_(2)/Ti薄膜的表面粗糙度逐渐增加;薄膜中(002)_(MoS_(2))和(100)_(MoS_(2))衍射峰的强度先减弱后增加;薄膜与基体的结合性能降低。当基体表面粗糙度为0.01μm时,干摩擦条件下MoS_(2)/Ti薄膜具有良好的润滑特性,平均摩擦因数为0.101,磨痕浅且小;随基体粗糙度的升高,样品的平均摩擦因数和磨损率均是先增大后减小,薄膜的主要磨损机制由磨粒磨损转变为屑片形成和破碎。当基体粗糙度较大时(R_(a)=0.26μm),分子间相互作用的影响大于机械啮合作用。采用固体-油复合润滑,高基体粗糙度的薄膜磨损表面不再出现片层剥落现象,磨痕较浅,平均摩擦因数最高可减小19%。固体-脂复合润滑条件下,样品摩擦磨损性能较差,基体粗糙度对摩擦因数的影响不显著。     

Synthesis and Characterization of(Na0.5K0.5)NbO3（NKN） Thin Films Formed by a Diol-based Sol-gel Process

Lead-free(Na_(0.5)K_(0.5))NbO_3(NKN) thin films were fabricated by spin coating on Pt/Ti/SiO2/Si substrates by a diol-based sol-gel process.Na-acetate,K-acetate,Nb-pentaethoxide and 1,3 propanediol were used to prepare the NKN precursor solution.Thermal analysis showed two characteristic temperatures of 360 and 600 ℃.Based on these temperatures,a heat treatment program with pyrolysis at 360 ℃ and calcination at 600 ℃ after every layer was used.To avoid inhomogeneities and secondary phases,an excess of sodium and potassium was necessary.To evaluate the proper excess amount of sodium and potassium secondary ion mass spectrometry(SIMS) lateral element maps and X-ray diffraction(XRD) patterns were recorded.An excess amount of 20% led to homogeneous distribution of the elements and to single phase perovskite NKN films with random crystal orientation.Scanning electron microscopy(SEM) images showed a pore free surface with 100 nm grains.The leakage current measurements showed a current of 1×10~(-3) A/cm~2 at 150 kV/cm.     

SiO2/TiO2 thin films with variable refractive index prepared by ion beam induced and plasma enhanced chemical vapor deposition

SiO₂/TiO₂ optical thin films with variable compositions have been prepared by ion beam induced and plasma enhanced chemical vapour deposition (IBICVD and PECVD). While the films obtained by IBICVD were very compact, the PECVD ones with a high content of Ti presented a columnar microstructure. The formation of Si–O–Ti bonds and a change in the environment around titanium from four- to six-coordinated has been proved by vibrational and X-ray absorption spectroscopies. The refractive index increased with the titanium content from 1.45 to 2.46 or 2.09 for, respectively, the IBICVD and PECVD films. Meanwhile, the band gap decreased, first sharply and then more smoothly up to the value of pure TiO₂. It is concluded that the optical properties of SiO₂/TiO₂ thin films can be properly tailored by using these two procedures.     

Improved tribological properties of sputtered MoS2 films through N implantation

The effect of N⁺ implantation on the microstructural and tribological properties of r.f.-sputtered MoS₂ films was studied. The cross-section scanning electron micrographs show that, after N⁺ implantation, the loose column structure of the sputtered MoS₂ films increases in density. A decrease in film thickness of about 50% is also observed. The results of X-ray diffraction analysis show that N⁺ bombardment enhances the (100) edge plane orientation of the MoS₂ crystal in the film. The scratch test indicates an improved film-substrate adherence. The tribological test results indicate that N⁺ implantation yields a distinct enhancement in the wear life of the sputtered MoS₂ films. Compared with the as-deposited MoS₂ film, the wear life of the sputtered MoS₂ films implanted with 150 keV N⁺ at 1 × 10¹⁶ N⁺ cm⁻² shows a threefold increase in a relative humidity of 60%–70% and a twofold increase in a vacuum of 5 × 10⁻³ Pa. However, N⁺ implantation inreases the friction coefficient. The lubrication model of the N⁺-modified film is given.     

Catalytic CVD growth and properties of a-C:H and a-C:N

Hydrogenated amorphous carbon (a-C:H) and nitrided amorphous carbon (a-C:N) films have been synthesized on quartz substrates at a substrate temperature of 700 °C using a catalytic chemical vapor deposition (Cat-CVD) method. Raman spectra of a-C:H films showed two principal bands, the G-band at 1600 cm⁻¹ and the D-band at 1350 cm⁻¹. Those of a-C:N films showed similar spectra, with a G′ band at 1640 cm⁻¹, the peak energy of which is higher than that of the G-band in a-C:H. The intensity ratio /I_D, which is a measure of the degree of order in a-C:H, decreased for a-C:H with increasing CH₄/H₂ gas-flow ratio. On the contrary, the /I_D ratio increased with increasing CH₄/H₂ gas-flow ratio.     

Effect of Nb, Cr, Sn additions on gas sensing properties of TiO2 thin films

The effect of Nb and Cr dopants as well as Sn⁴⁺ additions on the electronic structure of rf-sputtered TiO₂ thin films and its subsequent influence on gas sensor performance is reported. The changes in the electrical conductivities of TiO₂ thin films doped with up to 10 at.% Nb, 4 at.% Cr and TiO₂-SnO₂ in the full range of compositions upon exposure to hydrogen and oxygen are demonstrated. The spectral dependence of the absorption coefficient in the vicinity of the band gap transition of TiO₂ is shown to be affected by doping.     

新型纳米管状二硫化钼的制备

二硫化钼(MoS2)作为十分热门的材料,以其独特的物理和化学特性备受关注.纳米MoS2因其具有可调控带隙、 巨大的比表面积、丰富的边缘位点及良好的化学稳定性等优异的理化性质,在光电器件、催化、锂离子电池及超级电容器、润滑等领域有巨大的应用价值.介绍了采用化学气相沉积(CVD)法,在氩气保护氛围下,以三氧化钼粉末与硫粉作...     

宽带隙、高折射率聚偏四氟乙烯/TiO2-ZrO2光学膜的制备和表征

以氧氯化锆(ZrOCl₂·8H₂O)为锆源, 钛酸丁酯(Ti(OBu)₄)为钛源, 聚偏氟乙烯(PVDF)为有机添加剂, 采用溶胶–凝胶法在K9玻璃基片上制备PVDF/TiO₂-ZrO₂光学膜, 提高了ZrO₂-TiO₂光学膜的综合性能。然后采用SEM、FT-IR、接触角以及紫外/可见/近红外透射光谱等手段对PVDF/TiO₂-ZrO₂光学膜的组成、光学性能和抗激光损伤阈值进行了研究。SEM测试表明, 在K9玻璃基片上制备了光学膜。PVDF的添加导致水与薄膜的接触角增大。ZrO₂-TiO₂光学膜的光学带隙随ZrO₂含量的增加而略微增大, PVDF/ZrO₂(50mol%)-TiO₂薄膜的光学带隙随PVDF质量分数的增加而增大。另外, ZrO₂-TiO₂光学膜的折射率随ZrO₂摩尔分数的减小而增大, PVDF/ZrO₂(50mol%)-TiO2膜的折射率随PVDF质量分数的增加而增大。     

Growth of Ti:sapphire single crystal thin films by pulsed laser deposition

This paper documents the growth of single crystal Ti:sapphire thin films, typically 10 μm thick, on undoped sapphire substrates using pulsed laser deposition from a Ti:sapphire single crystal target with a doping level of 0.1 wt.% Ti₂O₃. These thin films are shown to have very high crystal quality using ion beam channelling and X-ray diffraction techniques. The degree of titanium incorporation into the films is investigated using inductively coupled plasma mass spectrometry and particle induced X-ray emission. These techniques show that levels of up to 0.08 wt.% Ti₂O₃ are present in the deposited layers.