1 湖南大学材料科学与工程学院,湖南光电集成创新研究院,湖南 长沙 410082
2 诺视科技(苏州)有限公司,江苏 苏州 215011
基于发光二极管的显示技术在电视、电脑、手机等终端产品上获得了广泛应用。与传统液晶显示器和有机发光二极管屏幕相比,微型发光二极管(Micro-LED)显示器件在尺寸、性能、功耗、使用寿命等方面均具有显著优势。总结了Micro-LED全彩色显示的技术类别和产品应用场景,综述了实现Micro-LED全彩色显示的最新研究进展,包括巨量转移技术、色转换层集成技术和外延芯片单片集成技术,并进一步比较分析这些技术的优缺点,展望了Micro-LED全彩色显示技术的未来发展。
发光二极管 显示技术 单片集成 巨量转移 氮化镓 激光与光电子学进展
2024, 61(1): 0125001
1 中国电子科技集团公司第十三研究所, 河北石家庄 050051
2 固态微波器件与电路全国重点实验室, 河北石家庄 050051
介绍了一款基于 GaAs肖特基二极管单片工艺的 220 GHz倍频器的设计过程以及测试结果。为提高输出功率, 倍频器采用多阳极结构, 8个二极管在波导呈镜像对称排列, 形成平衡式倍频器结构。采用差异式结电容设计解决了多阳极结构端口散射参数不一致问题, 提高了倍频器的转换效率和工作带宽。对设计的倍频器进行流片、装配和测试, 测试结果显示: 倍频器在 204~ 234 GHz频率范围内, 转化效率大于 15%; 226 GHz峰值频率下实现最大输出功率为 90.5 mW, 转换效率为 22.6%。设计的 220 GHz倍频器输出功率高, 转化效率高, 工作带宽大。
倍频器 太赫兹 肖特基二极管 结电容 单片 frequency doubler tearhertz Schottky barrier diode junction capacitance Microwave Monolithic Integrated Circuit 太赫兹科学与电子信息学报
2023, 21(9): 1080
1 中国民航大学,天津市民用航空器适航与维修重点实验室,天津 300300
2 河北工业大学机械工程学院,天津 300401
3 天津大学材料科学与工程学院,天津 300350
采用高温熔制法制备了1种CaO-MgO-Al2O3-SiO2非晶陶瓷材料,利用高速破碎技术和等离子喷涂技术在45号钢基体上制备得到钙镁铝硅酸盐陶瓷涂层。对块状陶瓷和涂层的物相组成、显微硬度和微观形貌进行了分析,通过拉伸实验测试了涂层的结合强度。通过盐溶液浸泡腐蚀实验研究了涂层的耐腐蚀性能和腐蚀机理。结果表明:钙镁铝硅酸盐陶瓷涂层的孔隙率为7.93%±3.27%,无明显层状结构,涂层显微硬度值为6.63 GPa,与块体材料相比仅降低了3.89%,非孔隙区域具有类块体陶瓷材料的显微结构和力学性能;涂层结合强度为(16.25±2.11)?偆bMPa,断裂发生在涂层与金属过渡层的界面处,与等离子喷涂其它陶瓷涂层的结合性能相当;通过1 000?偆bh的浸泡腐蚀实验得到涂层试样的腐蚀速率为0.102 6?偆bg瘙簚m-2瘙簚h-1,与基体试样相比降低了12.3倍,具有良好的耐腐蚀性能;分析腐蚀截面形貌发现,涂层的致密结构对腐蚀起机械隔绝作用,堆积在涂层孔隙与裂纹表面的腐蚀产物的溶解速率与腐蚀液渗至基体的速率达到平衡,减缓了腐蚀的发生。
钙镁铝硅酸盐 非晶陶瓷涂层 等离子喷涂 耐腐蚀性能 类块体材料 calcium magnesium aluminum silicate amorphous ceramic coating plasma spraying corrosion resistance monolithic like material
中国电子科技集团公司第十三研究所,河北石家庄 050051
基于 0.25 μm SiC衬底的 GaN高电子迁移率晶体管(HEMT)工艺,根据有源器件的 Gmax和输出功率密度,选择末级功率器件尺寸并确定其最优阻抗;采用三级放大器,其栅宽比为 1:4:16,实现高功率增益和高效率;利用等 Q匹配技术,把偏置电路融入匹配电路中,实现简单、低损耗和宽带阻抗变换;借助电磁场寄生参数提取技术实现紧凑型芯片版图,尺寸为 2.8 mm×2.0 mm。测试结果表明,偏置条件漏极电压 UD=28 V、UG=-2.2 V,在 2~6 GHz频率范围内,功率放大器增益大于 24 dB,饱和输出功率大于 43 dBm,功率附加效率大于 45%,可广泛应用于电子对抗和电子围栏等领域。
紧凑 功率附加效率 宽带 增益 微波单片集成电路 compact Power Additional Efficiency(PAE) broadband gain Monolithic Microwave Integrated Circuit(MMIC) 太赫兹科学与电子信息学报
2023, 21(8): 1054
中国工程物理研究院电子工程研究所, 四川绵阳 621999
基于单片微波集成电路技术设计了一款 S波段频率可调谐滤波器芯片, 该可调谐滤波器芯片采用信道化结构, 通过选择不同通道实现宽调谐比。其中每个通道采用多级放大器与无源滤波网络级联的形式提高该滤波电路的选择性, 通过在无源滤波网络引入变容二极管实现通道频率的连续调谐, 该结构可在滤波器具备较高选择性的前提下实现宽调谐比。采用 0.25 μm GaAs赝配高电子迁移率晶体管 (PHEMT)工艺设计了一款 S波段双通道信道化可重构滤波器, 仿真结果表明, 在 0~3 V控制电压范围下, 该滤波器中心频率调谐范围为 2.5~4 GHz, 带宽变化范围为 420~650 MHz, 调谐比达到 60%, 滤波器芯片尺寸为 3 mm×3.1 mm。该设计为片上可重构射频滤波实现宽频率调谐比提供了一条技术途径。
可重构滤波器 信道化滤波器 单片微波集成电路 宽调谐比 reconfigurable filter channelized filter Monolithic Microwave Integrated Circuit(MMIC) wide tuning ratio 太赫兹科学与电子信息学报
2023, 21(12): 1507
Author Affiliations
Abstract
1 Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices, Air Force Engineering University, Xi'an 710051, China
2 The Academy for Engineering & Technology, Fudan University, Shanghai 200433, China
Complex-amplitude holographic metasurfaces (CAHMs) with the flexibility in modulating phase and amplitude profiles have been used to manipulate the propagation of wavefront with an unprecedented level, leading to higher image-reconstruction quality compared with their natural counterparts. However, prevailing design methods of CAHMs are based on Huygens-Fresnel theory, meta-atom optimization, numerical simulation and experimental verification, which results in a consumption of computing resources. Here, we applied residual encoder-decoder convolutional neural network to directly map the electric field distributions and input images for monolithic metasurface design. A pretrained network is firstly trained by the electric field distributions calculated by diffraction theory, which is subsequently migrated as transfer learning framework to map the simulated electric field distributions and input images. The training results show that the normalized mean pixel error is about 3% on dataset. As verification, the metasurface prototypes are fabricated, simulated and measured. The reconstructed electric field of reverse-engineered metasurface exhibits high similarity to the target electric field, which demonstrates the effectiveness of our design. Encouragingly, this work provides a monolithic field-to-pattern design method for CAHMs, which paves a new route for the direct reconstruction of metasurfaces.
metasurface holography complex amplitude deep learning monolithic design Opto-Electronic Advances
2023, 6(8): 220148
1 上海第二工业大学资源与环境工程学院,上海 201209
2 上海第二工业大学能源与材料学院,上海 201209
本文通过浸没沉淀相转换法制备了具有整体式结构的氧化锌/氯氧化铋/氧化石墨烯/聚偏氟乙烯(ZnO/BiOCl/GO/PVDF)复合膜,以亚甲基蓝(MB)、罗丹明(RhB)和四环素(TC)为目标污染物验证了复合膜的光催化降解性能,通过XRD、SEM等测试方法对复合膜进行测试。结果表明,氯氧化铋(BiOCl)的薄片结构提供更多的活性位点,氧化石墨烯(GO)的褶皱状结构有利于ZnO的结合,有助于光催化效果的提升。同时ZnO与BiOCl形成p-n异质结,扩大复合材料的可见光响应范围,在可见光照射下,180 min时对RhB的去除率达95.5%,140 min时对TC的去除率达93.1%以上,能够基本去除污染物;循环使用5次后,复合膜对MB的降解率仍达97.8%。在“双碳”背景下,本文制备的具有整体式结构的ZnO/BiOCl/GO/PVDF复合膜可作为一种环保、稳定、经济的光催化剂,用于去除MB等水溶性污染物,该复合膜在整体式结构催化剂降解水溶性污染物废水中具有广阔的应用前景。
整体式结构 复合膜 双碳 光催化 水溶性污染物 ZnO ZnO BiOCl BiOCl monolithic structure composite membrane double carbon photocatalysis water-soluble pollutant
Yuheng Zeng 1,2,3,*†Zetao Ding 1,2,3†Zunke Liu 1,2,3Wei Liu 1,3[ ... ]Jichun Ye 1,2,3,***
Author Affiliations
Abstract
1 Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, CAS, Ningbo 315201, China
4 Zhejiang Energy Group R & D, Hangzhou 310003, China
In this work, we developed a simple and direct circuit model with a dual two-diode model that can be solved by a SPICE numerical simulation to comprehensively describe the monolithic perovskite/crystalline silicon (PVS/c-Si) tandem solar cells. We are able to reveal the effects of different efficiency-loss mechanisms based on the illuminated current density-voltage (J-V), semi-log dark J-V, and local ideality factor (m-V) curves. The effects of the individual efficiency-loss mechanism on the tandem cell’s efficiency are discussed, including the exp(V/VT) and exp(V/2VT) recombination, the whole cell’s and subcell’s shunts, and the Ohmic-contact or Schottky-contact of the intermediate junction. We can also fit a practical J-V curve and find a specific group of parameters by the trial-and-error method. Although the fitted parameters are not a unique solution, they are valuable clues for identifying the efficiency loss with the aid of the cell’s structure and experimental processes. This method can also serve as an open platform for analyzing other tandem solar cells by substituting the corresponding circuit models. In summary, we developed a simple and effective methodology to diagnose the efficiency-loss source of a monolithic PVS/c-Si tandem cell, which is helpful to researchers who wish to adopt the proper approaches to improve their solar cells.
monolithic perovskite/silicon tandem solar cell efficiency-loss analysis dual two-diode model SPICE numerical simulation Journal of Semiconductors
2023, 44(8): 082702