超高速大电流半导体开关实验研究

 利用自行研制的固态半导体开关RSD，采用电容储能方式，研究了RSD的电压响应时间、大电流特性、电流上升率等。在测试RSD的电压响应时间时，得到了25 ns的电压下降曲线。在主电容电压为8 kV时，得到峰值为10.1 kA、脉宽为34 μs、电流上升率为2.03 kA/μs的大电流脉冲。通过调整主电路，在主电容为3 kV时，得到的电流脉冲峰值为8.5 kA、脉宽为2.5 μs、电流上升率为7.2 kA/μs。结果表明，RSD是一种开通快、通流能力强、电流上升率高的大功率半导体开关器件。     

超高速脉冲晶闸管设计及特性

介绍一种超高速脉冲半导体器件,该器件属于穿通型器件,电压可达到5000V,电流上升率可以达到20kA/μs以上,根据参数调配,脉冲峰值电流可以达到数百kA。该器件采用多元胞集成结构,采用缓冲层与阳极透明层相结合的扩散技术,使其在压降和开通等方面相对于传统的晶闸管原理开关有更强的优势。并且,该超高速脉冲器件在工艺设计及实现上进行了优化,使生产条件易满足。     

两步式放电改善反向开关晶体管开通特性研究

针对大功率半导体开关反向开关晶体管(RSD)由于预充不足造成的非均匀开通缺陷, 在直接预充放电工作电路的基础上, 设计了一种两步式放电工作电路. 根据RSD结构特点理论分析了正常开通所需条件, 并对器件元胞结构进行建模分析, 模型仿真结果表明RSD在窄脉宽预充电流作用下具有更佳的开通性能, 降低了预充阶段基区载流子复合. 两步式放电实验发现第一步放电电流幅值、脉宽对于两步式放电电路的正常工作起决定作用, 而反向预充电流主要作用于RSD第一步放电的正常开通, 降低了预充电路设计难度. 仿真及实验结果均表明两步式放电电路较直接式预充放电电路提高了RSD的均匀开通性能, 这是由于两步式放电显著提高了基区等离子体积累.     

掺杂富勒烯衍生物阻变存储器存储性质的调控研究

以PS(聚苯乙烯)和PC_(61)BM([6.6]-苯基-C61-丁酸甲酯)为活性材料,通过加入导电性不同的缓冲层材料,优化了阻变存储器件的开关比。制备时分别以金纳米粒子(Au-NPs)、聚3,4-乙烯二氧噻吩/聚苯乙烯磺酸盐(PEDOT∶PSS)、聚乙烯吡咯烷酮(PVP)材料作为器件的缓冲层,得到了开关比可调、存储机制不同的电双稳态器件。测试结果发现缓冲层材料导电性是影响器件开关比的关键因素,当缓冲层材料从绝缘性材料PVP换为导电性良好的金纳米粒子,其开关比从10~2逐渐增大到10~5。另外对于不同结构的存储机制,通过电流电压拟合曲线和能带原理图分析,发现缓冲层材料的导电性质及能级匹配是影响器件存储机制的重要因素。     

基于果胶材料的阻变存储器离子缓冲层研究

采用微波辅助法制备了生物果胶薄膜,并作为缓冲层,制作了Ag/pectin/a-C/Pt阻变存储器.利用原子力显微镜表征薄膜表面的电流分布,探究了果胶薄膜的离子缓冲机理.分析了基于果胶薄膜的阻变存储器的阻变性能和阻变机制.结果表明:该缓冲层能够降低器件开关电压的波动性,提升高低阻态开关比.通过调控限制电流,在单一器件上实现了多阻态信息存储.     

聚合物微环谐振器电光开关阵列的优化与模拟

利用耦合模理论、电光调制理论和微环谐振理论,提出了一个聚合物微环谐振器电光开关阵列的模型.该器件由N-1个微环和N条平行信道构成,在微环上施加不同方式的驱动电压,可以实现N条信道的开关功能.以7微环8信道结构为例,在1550 nm谐振波长下对该器件进行了优化和模拟.结果表明,微环波导芯的截面尺寸为1.7μm×1.7μm,波导芯与电极间的缓冲层厚度为2.5 μm,电极厚度为0.2μm,微环半径为13.76 μm,微环与信道间的耦合间距为0.14μm,输出光谱的3 dB带宽约为0.05 nm,开关电压约为8.1 V左右,插入损耗约为0.23～4.6 dB,串扰小于-20 dB.     

F离子注入新型Al0．25Ga0．75N／GaNHEMT器件耐压分析

为了缓解AlGaN／GaNhighelectronmobilitytransistors（HEMT）器件n型GaN缓冲层高的泄漏电流,本文提出了具有氟离子注入新型Al0．25Ga0．75N／GaNHEMT器件新结构．首先分析得出n型GaN缓冲层没有受主型陷阱时,器件输出特性为欧姆特性,这样就从理论和仿真方面解释了文献生长GaN缓冲层掺杂Fe,Mg等离子的原因．利用器件输出特性分别分析了栅边缘有和没有低掺杂漏极时,氟离子分别注入源区、栅极区域和漏区的情况,得出当氟离子注入源区时,形成的受主型陷阱能有效俘获源极发射的电子而减小GaN缓冲层的泄漏电流,击穿电压达到262v通过减小GaN缓冲层体泄漏电流,提高器件击穿电压,设计具有一定输出功率新型A1GaN／GaNHEMT提供了科学依据．     

点接触金属/Pr0.7Ca0.3MnO3/Pt结构稳定的低电流电阻开关特性

利用自主开发的导电原子力显微镜控制Pt,W探针构成点接触金属/Pr0.7Ca0.3MnO3(PCMO)/Pt三明治结构,对其电流-电压(I-V)及脉冲诱导电阻开关(EPIR)特性进行了研究.研究发现,在10 nA限流下两种电极对应结构的I-V都表现出相当稳定的双极性电阻开关特性,以及大于100的电阻开关比.进一步测试发现,点接触W/PCMO/Pt器件具有在10 nA限流下稳定的EPIR特性以及100 pA限流下重复的双极性电阻开关特性.此电流比已报道的电流低3个数量级,表明此结构在低功耗存储器件方面的潜在应用.通过对比样品不同位置、不同限流、不同接触面积点接触Pt/PCMO/Pt的I-V回滞特性,把点接触器件在低电流下稳定、显著的电阻开关效应归结于小的器件面积导致强的局域电场加强了O离子迁移效应.     

MoO_3阳极缓冲层对有机太阳电池性能的影响

研究了MoO3阳极缓冲层对基于CuPc/C60异质结的有机小分子太阳电池器件性能的影响。发现:MoO3阳极缓冲层略微降低了器件的短路电流、开路电压及能量转换效率;MoO3阳极缓冲层提高了器件的整流比;具有MoO3阳极缓冲层的器件在持续光照条件下连续工作20min,其主要性能参数(如短路电流、开路电压、填充因子及能量转换效率)无明显衰减,而没有MoO3阳极缓冲层的对比器件在相同条件下连续工作20min,其能量转换效率衰减了大约45%。研究结果表明:MoO3阳极缓冲层明显提高了基于CuPc/C60异质结的有机小分子太阳电池器件的稳定性,可能的原因主要是MoO3阳极缓冲层改善了ITO阳极和CuPc界面,抑制了因持续光照连续工作引起的界面老化,从而提高了器件的稳定性。     

点接触金属/Pr$lt;sub$gt;0.7$lt;/sub$gt;Ca$lt;sub$gt;0.3$lt;/sub$gt;MnO$lt;sub$gt;3$lt;/sub$gt;/Pt结构稳定的低电流电阻开关特性

利用自主开发的导电原子力显微镜控制Pt,W探针构成点接触金属/Pr_0.7Ca_0.3MnO₃（PCMO）/Pt三明治结构,对其电流-电压（I-V）及脉冲诱导电阻开关（EPIR）特性进行了研究.研究发现,在10 nA限流下两种电极对应结构的I-V都表现出相当稳定的双极性电阻开关特性,以及大于100的电阻开关比.进一步测试发现,点接触W/PCMO/Pt器件具有在10 nA限流下稳定的EPIR特性以及100 pA限流下重复的双极性电阻开关特性.此电流比已报道的电流低3个数量级,表明此结构在低功耗存储器件方面的潜在应用.通过对比样品不同位置、不同限流、不同接触面积点接触Pt/PCMO/Pt的I-V回滞特性,把点接触器件在低电流下稳定、显著的电阻开关效应归结于小的器件面积导致强的局域电场加强了O离子迁移效应. 关键词： 脉冲诱导电阻开关 电场下氧离子迁移 电阻开关     

Ultrathin nickel oxide film as a hole buffer layer to enhance the optoelectronic performance of a polymer light-emitting diode

In order to promote a polymer LED (PLED), we fabricated and introduced an ultrathin nickel oxide (NiO) buffer layer (<10 nm) between the indium tin oxide (ITO) anode and the poly (3, 4-ethylenedioxythiophene) hole injection layer in the PLED. The NiO buffer layer was easily formed on the ITO anode by electron-beam deposition of a nickel (Ni) metal source and an oxygen plasma treatment process. As a result, the PLED device with the NiO buffer layer on its ITO anode had the same turn-on voltage as conventional PLED devices without the NiO buffer layer, and the luminance of the PLED device with the NiO buffer layer was doubled, compared with the conventional PLED devices without the NiO buffer layer. Improvement of the optoelectronic performance of the PLED can be attributed to the increase of the current driven into the diode, resulting from the NiO buffer layer, which can enhance the hole injection and balance the injection of the two types of carriers (holes and electrons). Thus it is an excellent choice to introduce the NiO buffer layer onto the ITO anode of the PLED devices in order to enhance the optoelectronic performance of PLED devices.     

氟化钇电子注入层对OLED器件性能的影响

利用氟化钇(YF3)代替Li F作为电子注入层材料,以金属铝作为阴极,制备了有机电致发光器件(OLED)。实验结果表明:适当厚度的YF3电子注入缓冲层可以增强阴极的电子注入能力,使得电子和空穴的浓度更加平衡,有效地提高器件的电致发光性能。其中,1.2 nm厚YF3的器件具有最小的起亮电压2.6 V,最高的电流效率8.52 cd·A-1,最大的亮度36 530 cd·m-2。最大亮度和电流效率与Li F参考样品相比,分别提高了39%和53%。     

Enhanced performance of the OLED with plasma treated ITO and plasma polymerized thiophene buffer layer

In this work, indium-tin-oxide (ITO) electrode in organic light emitting device (OLED) was modified by using an O₂ plasma treatment and plasma polymerized thiophene buffer layers were inserted between ITO (anode) and organic layer in order to improve the hole injection efficiency. Furthermore, electron injection to cathode (Al) in the test OLED seemed to be improved due to introduction of quantum well in the cathode. The plasma-polymerized thiophene buffer layer on the O₂ plasma-treated transparent ITO electrode seemed to result in formation of a stable interface and consequently, reduction the hole mobility, which in turn caused enhanced recombination of hole and electron in the emitting layer. Compared with the test device without buffer layer, the turn-on voltage of the test device with the buffer layer was lowered by 1.0 V.     

White light electroluminescence from poly(9-vinylcarbazole) (PVK)/ZnO NRs/poly(2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene) (MEH-PPV) dual heterojunctions

In this paper, we fabricated a p-PVK/n-ZnO nanorods (NRs)/p-MEH-PPV dual heterojunctions white light-emitting diode. Relative to previously reported p–n heterojunction structure including ZnO NRs and polymer, the device exhibits a low turn-on voltage of 7 V. An obviously broad electroluminescence emission band, originated from the overlap of PVK emission and ZnO defects emissions, was observed extending from 360 up to 700 nm. The influence of the two introduced p-type polymer layers on the device characteristic is discussed. With its hole conductivity, the p-PVK layer cannot only improve the holes tunnel into ZnO NRs layer, but also lower the barrier between ITO and the valance band of ZnO NRs. On the other hand, p-MEH-PPV could be regarded as block layer for the injection of electrons from the Al electrode. Both of two p-type polymers dramatically improve the injection balance of carriers, leading to a low turn-on voltage. Meanwhile, the carrier transport mechanism of the device under different forward bias region was discussed on the basis of current–voltage curve.     

以ILTO为阳极的高效有机电致发光器件

以高功函数的掺杂钛酸镧的氧化铟薄膜(ILTO)及氧化铟锡(ITO)作为阳极,制备了Glass/anode/NPB/Alq3/LiF/Al结构的有机电致发光器件。得益于ILTO较好的掺杂性、低的表面粗糙度、高的可见光透过率以及高的有效功函数,以ILTO为阳极的有机电致发光器件的开路电压得到降低,最高亮度、电流效率、功率效率以及外量子效率均获得了成倍的提高。研究结果表明,ILTO是一种潜在的光学窗口材料,有望在各种光电器件中得到广泛的应用。     

Electro-optical properties of all-oxide p-CuAlO<Subscript>2</Subscript>/n-ZnO: Al transparent heterojunction thin film diode fabricated on glass substrate

We report on the fabrication of all transparent heterojunction thin film diodes of the form glass/n-ZnO: Al/p-CuAlO₂ produced by a combinatorial chemical and physical technique and on a study of their electro-optical properties. The n-ZnO: Al layer was deposited by a sol-gel-dip-coating process whereas the p-CuAlO₂ layer was deposited by direct current sputtering techniques. The diode structure, with a total thickness of 1100 nm showed around 60% transmittance in the visible region. The current-voltage characteristics of the device showed a rectifying nature, with a low turn-on voltage around 0.8 V, having a rectification ratio > 50 at ± 2 V. The low turn-on voltage and moderate visible transmittance of the transparent diode indicate its potential application in the field of “Transparent” or “Invisible Electronics”.      

Highly efficient and low turn-on voltage quantum-dot light-emitting diodes using a ZnMgO/ZnO double electron transport layer

A ZnMgO and ZnO double-layered structure was prepared to create a stepwise interfacial electronic structure to improve the electron-injection and electron-transport behaviors in quantum-dot light-emitting diodes (QLEDs). The current density of the electron-only device (EOD) with ZnMgO/ZnO was higher than that of the EOD with only ZnMgO. The detailed QLED interfacial electronic structure was measured using X-ray and ultraviolet photoelectron spectroscopy. A stepwise interfacial electronic structure for electron injection and electron transport was observed connecting the aluminum cathode to the ZnMgO conduction band minimum (CBM) via the ZnO CBM. The QLEDs with the ZnMgO/ZnO double electron transport layer showed an improved performance, with a maximum luminance and current efficiency of 90,892 cd m⁻² and 19.2 cd A⁻¹, respectively. Moreover, the turn-on voltage of the device was significantly reduced to 2.6 V due to the stepwise interfacial electronic structure between the aluminum cathode and ZnMgO CBM. This research provides a useful method for developing highly efficient and low turn-on voltage QLEDs using a ZnMgO/ZnO double ETL for next-generation display.