A field-effect WSe2/Si heterojunction diode

It is significant to develop a heterogeneous integration technology to promote the application of two-dimensional (2D) materials in silicon roadmap. In this paper, we reported a field-effect WSe₂/Si heterojunction diode based on ambipolar 2D WSe₂ and silicon on insulator (SOI). Our results indicate that the device exhibits a p-n diode behavior with a rectifying ratio of ～ 300 and an ideality factor of 1.37. As a photodetector, it has optoelectronic properties with a response time of 0.13 ms, responsivity of 0.045 A/W, detectivity of 4.5×10¹⁰ Jones and external quantum efficiency (EQE) of 8.9 %. Due to the ambipolar behavior of the WSe₂, the rectifying and optoelectronic properties of the heterojunction diode can be modulated by the gate electrical field, enabling various potential applications such as logic optoelectronic devices and neuromorphic optoelectronic devices for in-sensor computing circuits. Thanks to the process based on the mature SOI technique, our field-effect heterojunction diode should have obvious advantages in device isolation and integration.     

基于双极性二维晶体的新型p-n结

二维晶体的特殊结构和新奇物理性能为构建新型纳米结构和器件,实现半导体领域的突破性进展提供了可能.本文首先介绍了双极性二维晶体的基本物理性能和相关范德瓦耳斯异质结的制备方法.在此基础上,主要综述了双极性二维晶体在新型电场调制二维晶体p-n结与异质p-n结以及非易失性可存储二维晶体p-n结等方面的应用、相关结构设计、电子和光电子等物理性能.然后进一步介绍了该类新型p-n结在逻辑整流电路、场效应光电子晶体管、多模式非易失性存储器、整流存储器、光电子存储器、光伏器件等方面的潜在应用.最后总结展望了该种新型p-n结在相关领域的可能发展方向.     

Electron field emission from single-walled carbon nanotube nonwoven

Field emission from single-walled carbon nanotube (SWNT) nonwoven has been investigated under high vacuum with different vacuum gaps. A low turn-on electric field of 1.05\,V/$\mu $m is required to reach an emission current density of 10 $\mu $A/cm$^{2}$. An emission current density of 10 mA/cm$^{2}$ is obtained at an operating electric field of 1.88\,V/$\mu $m. No current saturation is found even at an emission current of 5\,mA. With the vacuum gap increasing from 1 to 10 mm, the turn-on field decreases monotonically from 1.21 to 0.68\,V/$\mu $m, while the field amplification is augmented. The good field-emission behaviour is ascribed to the combined effects of the intrinsic field emission of SWNT and the waved topography of the nonwoven.     

Synthesis and characterization of axially periodic Zn2SnO4 dendritic nanostructures

Zn2SnO4 （ZTO） nanowires with a unique dendritic nanostructure were synthesized via a simple one-step thermal evaporation and condensation process. The morphology and microstructure of the ZTO nanodendrite have been investigated by means of field emission scanning electron microscopy （SEM）, x-ray diffraction （XRD） and high-resolution transmission electron microscopy （HRTEM）. SEM observation revealed the formation of branched nanostructures and showed that each branch exhibited a unique periodic structure formed by a row of overlaid rhombohedra of ZTO nanocrystals along the axis of the nanobranch. HRTEM studies displayed that the branches grew homoepitaxially as single-crystalline nanowires from the ZTO nanowire backbone. A possible growth model of the branched ZTO nanowires is discussed. To successfully prepare branched structures would provide an opportunity for both fundamental research and practical applications, such as three-dimensional nanoelectronics, and opto-electronic nanodevices.     

Growth of aligned single-walled carbon nanotubes under ac electric fields through floating catalyst chemical vapour deposition

Through floating catalyst chemical vapour deposition(CVD) method,well-aligned isolated single-walled carbon nanotubes (SWCNTs) and their bundles were deposited on the metal electrodes patterned on the SiO₂/Si surface under ac electric fields at relatively low temperature(280℃). It was indicated that SWCNTs were effectively aligned under ac electric fields after they had just grown in the furnace.The time for a SWCNT to be aligned in the electric field and the effect of gas flow were estimated. Polarized Raman scattering was performed to characterize the aligned structure of SWCNTs. This method would be very useful for the controlled fabrication and preparation of SWCNTs in practical applications.     

Seed-mediated growth of gold nanoparticles using self-assembled monolayer of polystyrene microspheres as nanotemplate arrays

Arrays of noble metal nanoparticles show potential applications in (bio-)sensing, optical storage, surface-enhanced spectroscopy, and waveguides. For all such potential devices, controlling the size, morphology, and interparticle spacing of the nanoparticles is very important. Here, we combine seed-mediated growth with nanosphere lithography to study the controllable growth of gold nanoparticles (Au NPs), in which the self-assembly monolayer of polystyrene (PS) on a silicon surface is used to guide the modification of alkanesilanes and the subsequent adsorption of gold seeds; seed-mediated growth is applied to controlling the morphology and size of Au NPs. The size of adsorption region (determining the number of adsorbed gold seeds) is controlled by etching PS microspheres with oxygen plasma or annealing PS microspheres at the glass transition temperature. The size and morphology of the Au NPs are controlled by changing growth conditions. In such a way, we have achieved the dual control of the obtained Au NPs. Preliminary results show that this strategy holds a great promise. This approach can also be extended to a wide range of materials and substrates.     

磁悬浮式电磁-摩擦复合生物机械能量采集器

能量采集技术已经成为智能终端领域的一项关键技术,关于人体机械能采集方式也有大量的研究.针对人体机械能采集的应用需求,本文提出一种基于磁悬浮结构的电磁-摩擦复合式能量采集器.该能量采集器以磁悬浮结构作为核心部件,具有结构简单、感应灵敏、输出功率高的优点.在10 MΩ的外接负载时,两组摩擦发电单元输出功率分别为0.12 mW和0.13 mW;在1kΩ外接负载时,两组电磁发电单元的输出功率分别为36 mW和38 mW.复合能量采集器通过电容储能后,电容器可以输出8 V电压,且输出信号为持续的直流信号,可以为计步器提供持续的能量供给,支撑计步器正常工作.设计的复合能量采集器对于可穿戴电子设备自供电工作模式的实现具有重要意义.     

微米/纳米相结合的三维金属铝图案

利用光刻，反应离子刻蚀以及电化学阳极氧化技术在铝基底上构建出了微米纳米相结合的三维金属铝图案。首先在铝片的表面形成一层具有图案的二氧化硅阻碍层，阳极氧化过程中，在二氧化硅阻碍层之下会形成侧向生长的倾斜孔道和残留的金属铝微结构。形成机制可阐述为：由于表面二氧化硅阻碍层的存在造成局域电场方向的偏折，影响到反应过程中离子的输运，从而导致侧向倾斜孔的形成，而在远离阻碍层的区域孔道则会正常垂直表面向下生长。这种垂直与侧向阳极腐蚀的同时进行导致在二氧化硅阻碍层之下形成了金属铝微结构。     

纳米集成光路中的光源、光波导和光增强

使用近场光学显微术(scanning near-field optical microscopy, SNOM)研究了ZnO亚微米线端面出射性质,不同空间形貌Ⅱ-Ⅵ族半导体荧光器件光波导特性,二维光子晶体、准晶光子晶体对LED的出射增强作用以及表面等离激元(surface plasmon polariton, SPP)与半导体纳米荧光器件的相互作用,对纳米集成光路中的光源、光波导、光增强三个重要问题做了实验和理论上的分析.研究发现半导体微纳米线端面出射光束的质量与样品的直径有密切关系.通过合理地设计其直径和 关键词： 纳米集成光路 扫描近场光学显微术 光波导 光增强     

纳米集成光路中的光源、光波导和光增强

使用近场光学显微术(scanning near-field optical microscopy, SNOM)研究了ZnO亚微米线端面出射性质，不同空间形貌Ⅱ-Ⅵ族半导体荧光器件光波导特性，二维光子晶体、准晶光子晶体对LED的出射增强作用以及表面等离激元(surface plasmon polariton, SPP)与半导体纳米荧光器件的相互作用，对纳米集成光路中的光源、光波导、光增强三个重要问题做了实验和理论上的分析.研究发现半导体微纳米线端面出射光束的质量与样品的直径有密切关系.通过合理地设计其直径和