薄膜厚度对ZnO：Al透明导电膜性能的影响

铝掺杂的氧化锌 (ZnO∶Al)透明导电膜是采用射频磁控溅射法在有机衬底 (Polypro pyleneadipate,PPA)和Corning 70 5 9玻璃上制备的。详细研究了薄膜的结构性质、光学和电学性质随薄膜厚度的变化关系。制备的ZnO∶Al薄膜具有 (0 0 2 )面的单一择优取向的多晶六角纤锌矿结构 ,性能优良的薄膜电阻率在两种衬底上分别为 2 .5 5× 1 0 - 3 Ω·cm和1 .89× 1 0 - 3 Ω·cm ,平均透射率达到了 80 %和 85 %。     

可穿戴设备续航能力研究的新进展北大核心

分析了可穿戴设备的现状和发展中存在的问题,并指出制约可穿戴设备发展最重要的因素——续航能力。总结了续航能力研究的两个主要方向,一是电池技术的创新,阐述了通过寻找新电极和电解质材料研究新型电池,详细介绍了锂氟化碳电池、固态锂电池、纳米电池、柔性锂电池等锂电池研究的新进展,以及为了提高太阳电池的光电转换效率,概述了薄膜太阳电池、钙钛矿太阳电池等太阳电池的新研究成果;二是优化电路设计,提供高效的电源管理,并将蓝牙、微处理器和无线通信等模块中的高功耗芯片设计成低功耗。最后,对可穿戴设备的发展趋势进行了展望。     

基于ZigBee与OpenWrt的植物生长环境的监测及控制系统

介绍了一种基于ZigBee与OpenWrt的植物生长环境监测及控制系统的设计方法。该系统采用多个传感器节点采集生长环境数据并进行预处理后发给协调器节点,由协调器节点经I2C接口将数据发送给路由器单元进行多数据融合,更客观、真实地反映各个传感器的测量数据。结果表明该系统具有实时视频监控、数据显示、处理分析、记录存储以及远程控制等功能。     

柔性可穿戴电子的新进展

综述了近期柔性可穿戴电子的研究进展以及在现代生活中的发展应用,阐明了柔性薄膜电子在医学和生活娱乐等领域的发展方向和潜在应用,特别是在医疗领域,柔性电子的发展与应用将是人们未来生命健康监测与治疗的主流方向。详细介绍了以聚酰亚胺等聚合物材料为基底的薄膜电子器件的发展类型,并且阐述了分别以聚合物薄膜材料和导电织物为基底的柔性电子设计。论述了制约柔性可穿戴电子在未来发展研究中的问题,并对柔性可穿戴电子的发展趋势进行了展望。     

GaN紫外光电导探测器的研究

回顾了近几年在 Ga N紫外光电导探测器上的研究进展 ,介绍了不同 Ga N光电导紫外光探测器的制备方法、光电参数及工作机理。     

Fabrication and optical properties of MgxZn1-xO thin films

MgxZn1xO (x ≤ 0.3) thin films have been prepared on silicon substrates by radio frequency magnetron sputtering at room temperature. The thin films have hexagonal wurtzite single-phase structure and a preferred orientation with the c-axis perpendicular to the substrates. The Mg content in the films is slightly larger than that in the targets. The refractive indices of MgxZn1xO films measured at room temperature by spectroscopic ellipsometry (SE) on the wavelength 632.8 nm are systematically decreased with the increasing of Mg content. Optical band gaps of Mg x Zn 1 x O films are determined by the transmittance spectra. With increasing Mg content, the absorption edges of MgxZn1xO films shift to higher energies and band gaps linearly increase from 3.24 eV at x=0 to 3.90 eV at x=0.30.     

超薄SiO2/HfO2双层栅介质的时变击穿特性和击穿机制的研究

The characteristics of TDDB （time-dependent dielectric breakdown） and SILC （stress-induced leakage current） for an ultra-thin SiO2/HfO2 gate dielectric stack are studied. The EOT （equivalent-oxide-thickness） of the gate stack （Si/SiO2/HfOz/TiN/TiA1/TiN/W） is 0.91 am. The field acceleration factor extracted in TDDB experi- ments is 1.59 s.cm/MV, and the maximum voltage is 1.06 V when the devices operate at 125 ℃ for ten years. A detailed study on the defect generation mechanism induced by SILC is presented to deeply understand the break- down behavior. The trap energy levels can be calculated by the SILC peaks： one S1LC peak is most likely to be caused by the neutral oxygen vacancy in the HfO2 bulk layer at 0.51 eV below the Si conduction band minimum; another SILC peak is induced by the interface traps, which are aligned with the silicon conduction band edge. Fur- thermore, the great difference between the two SILC peaks demonstrates that the degeneration of the high-k layer dominates the breakdown behavior of the extremely thin gate dielectric.     

Efficiency improvement of AlGaN-based deep ultraviolet LEDs with gradual Al-composition AlGaN conduction layer

The low internal quantum efficiency (IQE) of AlGaN-based deep ultraviolet light emitting diode (DUV-LED) limits its wider application. The main reasons for low IQE include low carrier concentration, poor carrier location and large defects. The bending of energy band between AlGaN electron blocking layer and conduction layer obstructs transport of holes to multiple quantum wells. In this paper, we propose a gradual Al-composition p-type AlGaN (p-AlGaN) conduction layer to improve the light emitting properties of AlGaN-based DUV-LED. Increased carrier concentration in the active region enhances the effective radiative recombination rate of the LED. Consequently, the IQE of our optimazited DUV-LED is increased by 162% in comparison with conventional DUV-LEDs.     

射频磁控溅射法制备ZnO薄膜的发光特性

利用射频磁控溅射法在硅衬底上制备出具有（002）择优取向的氧化锌薄膜，用波长为300nm的光激发，观察到在446nm处有一强的光致发光峰，它来自于氧空位浅施主能级上的电子到价带上的跃迁。并讨论了发光峰与氧压的关系以及退火对它的影响，且给出了解释。     

Structure Properties of MgxZn1-xO Films Deposited at Low Temperature

MgxZn1-xO films (x = 0.23) have been prepared on silicon substrates by radio-frequency magnetron sputtering at 80℃. The structure properties of Mgx Zn1-xO films are studied using x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy and Raman spectra. The analysis of XRD and HRTEM indicates that the Mgx Zn1-xO films have hexagonal wurtzite single-phase structures and a preferred orientation with the c axis perpendicular to the substrates. Raman spectra of ZnO and MgxZn1-xO films reveal that the MgxZn1-xO films have not only the hexagonal wurtzite structure but also higher crystalline quality than ZnO films.