The glass-forming ability of binary GexTe100-x (x=15, 20, 30) alloys was investigated. The crystallization mechanism of these amorphous bulks was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) ...The glass-forming ability of binary GexTe100-x (x=15, 20, 30) alloys was investigated. The crystallization mechanism of these amorphous bulks was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calo- rimetry (DSC). The temperature of glass transition, the temperature of crystallization, the activation energy for glass transition and crystallization, and the order of the crystallization mechanism were calculated from the different heating-rates.展开更多
The change trends of the glass structure of the three component system AsGe-Te were studied by the method EXAFS, based on the phase diagram works of this system. That provides scientific basis for the preparation and ...The change trends of the glass structure of the three component system AsGe-Te were studied by the method EXAFS, based on the phase diagram works of this system. That provides scientific basis for the preparation and the application of the above-mentioned system.展开更多
针对传统加热器中置间接加热相变开关的固有切换速度缓慢难题,本文提出一种加热器顶置的射频开关新结构,即加热器顶置的间接加热相变材料四端口开关(four-port indirect heating phase change switch with a top microheater,FIPCS-T),...针对传统加热器中置间接加热相变开关的固有切换速度缓慢难题,本文提出一种加热器顶置的射频开关新结构,即加热器顶置的间接加热相变材料四端口开关(four-port indirect heating phase change switch with a top microheater,FIPCS-T),通过热传导过程自上而下的定向性,建立了更加有效的焦耳热能量利用方法.新结构中不同射频参数的仿真表明,FIPCS-T结构对升温过程和淬火过程均能有效缩短相变材料达到临界温度的时间,升温过程比淬火过程的缩短更加显著.相比于传统中置间接加热相变开关,FIPCS-T的升温-淬火环节时间缩短20%以上,这不仅显著提高了切换速度,同时还降低了相变材料的重结晶风险,结合相变材料本身具有的高频低损耗特征及其器件结构设计的灵活性,从而可在微波、毫米波、太赫兹等超大范围频段内提供反射小、插损低和端口隔离度高的高速射频开关.尽管人们对GeTe相变材料在信息存储等方面的应用开展了多年研究,但其特殊相变特征能否解决未来射频开关面临的高性能需求,仍然存在诸多挑战.本文研究结果表明,GeTe热相变机理与PIN二极管、微机电系统(microelectromechanical systems,MEMS)等其他原理相比,新射频开关的速度更快、工作频率更高、插入损耗更低.在射频开关特性验证的基础上,我们构建了由5个FIPCS-T单元组成的缺陷地结构(defected ground structure,DGS)可重构滤波器,实现了滤波器频率和带宽的重构,证明了开关状态组合对滤波器媒质特性的调控能力;再通过5个单元FIPCS-T开关状态的组合与电致热控制,实现了低通、带通滤波特征的可重构,为未来大规模天线、大规模电路等先进可重构无线电系统的智慧调控提供了全新的射频开关机理和方法.同时,引入类似相变存储器多值方案的控制方法,可有效提升相变开关的调控和选择维度,增加可调控的性能范围和参数,实现其他类型开关不能实现的更深层次调控优势.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No.50601022 and 50471039).
文摘The glass-forming ability of binary GexTe100-x (x=15, 20, 30) alloys was investigated. The crystallization mechanism of these amorphous bulks was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calo- rimetry (DSC). The temperature of glass transition, the temperature of crystallization, the activation energy for glass transition and crystallization, and the order of the crystallization mechanism were calculated from the different heating-rates.
文摘The change trends of the glass structure of the three component system AsGe-Te were studied by the method EXAFS, based on the phase diagram works of this system. That provides scientific basis for the preparation and the application of the above-mentioned system.
文摘针对传统加热器中置间接加热相变开关的固有切换速度缓慢难题,本文提出一种加热器顶置的射频开关新结构,即加热器顶置的间接加热相变材料四端口开关(four-port indirect heating phase change switch with a top microheater,FIPCS-T),通过热传导过程自上而下的定向性,建立了更加有效的焦耳热能量利用方法.新结构中不同射频参数的仿真表明,FIPCS-T结构对升温过程和淬火过程均能有效缩短相变材料达到临界温度的时间,升温过程比淬火过程的缩短更加显著.相比于传统中置间接加热相变开关,FIPCS-T的升温-淬火环节时间缩短20%以上,这不仅显著提高了切换速度,同时还降低了相变材料的重结晶风险,结合相变材料本身具有的高频低损耗特征及其器件结构设计的灵活性,从而可在微波、毫米波、太赫兹等超大范围频段内提供反射小、插损低和端口隔离度高的高速射频开关.尽管人们对GeTe相变材料在信息存储等方面的应用开展了多年研究,但其特殊相变特征能否解决未来射频开关面临的高性能需求,仍然存在诸多挑战.本文研究结果表明,GeTe热相变机理与PIN二极管、微机电系统(microelectromechanical systems,MEMS)等其他原理相比,新射频开关的速度更快、工作频率更高、插入损耗更低.在射频开关特性验证的基础上,我们构建了由5个FIPCS-T单元组成的缺陷地结构(defected ground structure,DGS)可重构滤波器,实现了滤波器频率和带宽的重构,证明了开关状态组合对滤波器媒质特性的调控能力;再通过5个单元FIPCS-T开关状态的组合与电致热控制,实现了低通、带通滤波特征的可重构,为未来大规模天线、大规模电路等先进可重构无线电系统的智慧调控提供了全新的射频开关机理和方法.同时,引入类似相变存储器多值方案的控制方法,可有效提升相变开关的调控和选择维度,增加可调控的性能范围和参数,实现其他类型开关不能实现的更深层次调控优势.
