提出了一种金纳米十字双层等离子体结构阵列(BPNA), 采用有限时域差分法(FDTD), 计算了金纳米十字孔阵列、金纳米十字薄片阵列、二氧化硅阵列对结构透射性能的影响。计算得出的透射光谱中, 三者均对局域表面等离子激元(LSP)产生了影响, 产生的LSP共振峰强度和位置取决于十字孔的宽度、长度以及厚度和十字薄片的宽度、长度以及厚度, 通过增加介质层厚度分析出两个LSP共振峰的产生原因主要取决于十字孔缝产生的LSP或十字薄片产生的LSP, 而替换二氧化硅选用理想介质同样对LSP共振峰产生影响。对等离子体结构进行参数调节可以改变其透射性能, 调节后的半峰宽度(FWHM)高达0.72m, 透射强度高达0.96, 可以用来实现天线的高性能传输, 还获得了较高的灵敏度(FOM)值为17.22m/RIU, 对实现高性能的LSP传感器和光学器件有一定借鉴意义。
双层等离子体结构阵列 局域表面等离子体共振 半峰宽度 灵敏度 bi-layer plasmonic nanostructure array localized surface plasmon full width at half maxima figure of merit 量子光学学报
2023, 29(4): 040801
光子学报
2023, 52(10): 1052415
1 河北工业大学理学院, 天津 300401
2 北华航天工业学院电子与控制工程学院, 廊坊 065000
本文利用第一性原理计算并结合玻尔兹曼输运方程, 预测了一种热电性能优良的新型Bi2Te3基材料, 即单层BiSbTeSe2。通过系统计算单层BiSbTeSe2的电子能带结构和热电输运性质, 发现单层BiSbTeSe2在300 K时的塞贝克系数达到最高值(522 μV· K-1), 在500 K时功率因子与弛豫时间的比值最大为5.78 W· m-1·K-2·s-1。除此之外, 单层BiSbTeSe2还具有较低的晶格热导率和较高的迁移率。在最佳p型掺杂下, 单层BiSbTeSe2在500 K时的热电优值 ZT高达3.95。单层BiSbTeSe2的优良性能表明其在300~500 K的中温热电器件领域具有潜在的应用价值, 可以为进一步开发高性能Bi2Te3基热电材料提供设计依据。
第一性原理 Bi2Te3基材料 电子结构 热电输运 热电优值 层状材料 first-principle Bi2Te3-based material electronic structure thermoelectric transport thermoelectric figure of merit layered material
Author Affiliations
Abstract
1 Soft Matter Physics, Johannes Kepler University, Altenbergerstraße 69, 4040 Linz, Austria
2 Institute of Applied Sciences & Intelligent Systems, National Research Council (CNR-ISASI), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
The characterization of pyroelectric materials is essential for the design of pyroelectric-based devices. Pyroelectric current measurement is the commonly employed method, but can be complex and requires surface electrodes. Here, we present noncontact electrostatic voltmeter measurements as a simple but highly accurate alternative, by assessing thermally-induced pyroelectric surface potential variations. We introduce a refined model that relates the surface potential variations to both the pyroelectric coefficient and the characteristic figure of merit (FOM) and test the model with square-shaped samples made from PVDF, LiNbO3 and LiTaO3. The characteristic pyroelectric coefficient for PVDF, LiNbO3 and LiTaO3 was found to be 33.4, 59.9 and 208.4 C m K, respectively. These values are in perfect agreement with literature values, and they differ by less than 2.5% from values that we have obtained with standard pyroelectric current measurements for comparison.
Pyroelectric coefficient surface potential figure of merit Journal of Advanced Dielectrics
2023, 13(4): 2341002
Author Affiliations
Abstract
National Key Laboratory of Application Specific Integrated Circuit (ASIC), Hebei Semiconductor Research Institute, Shijiazhuang 050051, China
This work demonstrates high-performance NiO/β-Ga2O3 vertical heterojunction diodes (HJDs) with double-layer junction termination extension (DL-JTE) consisting of two p-typed NiO layers with varied lengths. The bottom 60-nm p-NiO layer fully covers the β-Ga2O3 wafer, while the geometry of the upper 60-nm p-NiO layer is 10 μm larger than the square anode electrode. Compared with a single-layer JTE, the electric field concentration is inhibited by double-layer JTE structure effectively, resulting in the breakdown voltage being improved from 2020 to 2830 V. Moreover, double p-typed NiO layers allow more holes into the Ga2O3 drift layer to reduce drift resistance. The specific on-resistance is reduced from 1.93 to 1.34 mΩ·cm2. The device with DL-JTE shows a power figure-of-merit (PFOM) of 5.98 GW/cm2, which is 2.8 times larger than that of the conventional single-layer JTE structure. These results indicate that the double-layer JTE structure provides a viable way of fabricating high-performance Ga2O3 HJDs.
β-Ga2O3 breakdown voltage heterojunction diode (HJD) junction termination extension (JTE) power figure-of-merit (PFOM) Journal of Semiconductors
2023, 44(7): 072802
1 衢州职业技术学院信息工程学院,浙江 衢州 324000
2 绍兴文理学院数理信息学院,浙江 绍兴 312000
提出了一种结构简单且可激发环偶极子共振的全介质超材料,该超材料具有高品质因子(Q)和高灵敏(FOM)值。基于环偶极子共振电流密度和电场分布,分析了超材料能够激发环偶极子的内在物理机制。经模拟计算发现,全介质超材料的Q值和FOM值可分别达到14000以上和672.7/RIU左右。基于谐振子耦合模型和共振波长处的电场分布,分析了超材料全介质开口环间距和探测物厚度对其Q值和环偶极子共振波长的影响机理。该研究可以为设计制备应用于生物、化学探测的高质量环偶极子共振超材料传感器提供理论基础。
光纤光学与光通信 环偶极子 超材料 品质因子 灵敏值 激光与光电子学进展
2023, 60(9): 0906011
1 1.山东大学 材料科学与工程学院, 材料液固结构演变与加工教育部重点实验室, 济南 250061
2 2.齐鲁工业大学(山东省科学院) 化学与化工学院, 济南 250353
钛酸钡(BaTiO3)具有优异的介电、铁电、压电和热释电等性能, 在微电子机械系统和集成电路领域具有广泛的应用。降低BaTiO3薄膜的制备温度使其与现有的CMOS-Si工艺兼容, 已成为应用研究和技术开发中亟需解决的问题。本研究引入与BaTiO3晶格常数相匹配的LaNiO3作为缓冲层, 以调控其薄膜结晶取向, 在单晶Si(100)基底上450 ℃溅射制备了结构致密的柱状纳米晶BaTiO3薄膜。研究表明:450 ℃溅射温度在保持连续柱状晶结构和(001)择优取向的前提下, 能获得相对较大的柱状晶粒(平均晶粒直径27 nm), 一定残余应变也有助于其获得了较好的铁电和介电性能。剩余极化强度和最大极化强度分别达到了7和43 μC·cm-2。该薄膜具有良好的绝缘性, 在 0.8 MV·cm-1电场下, 漏电流密度仅为10-5 A·cm-2。其相对介电常数εr展现了优异的频率稳定性:在1 kHz时εr为155, 当测试频率升至1 MHz, εr仅轻微降低至145。薄膜的介电损耗较小, 约为0.01~0.03 (1 kHz ~ 1 MHz)。通过电容-电压测试, 该薄膜材料展示出高达51%的介电调谐率, 品质因子亦达到17(@1 MHz)。本研究所获得的BaTiO3薄膜在介电调谐器件中有着良好的应用前景。
硅 BaTiO3 铁电薄膜 柱状纳米晶 介电调谐率 品质因子 silicon BaTiO3 ferroelectric film columnar nanograins dielectric tunability figure of merit
Author Affiliations
Abstract
1 School of Mathematics & Physics, Hebei University of Engineering, Handan 056038, China
2 School of Information & Electrical Engineering, Hebei University of Engineering, Handan 056038, China
A high performance optical sensor based on a double compound symmetric gratings (DCSGs) structure is designed. The reflection spectrum of the DCSG is investigated by utilizing a method that combines a theoretical model with the eigenmode information of the grating structure. The theoretical results, which are observed to agree well with those acquired by rigorous coupled-wave analysis, show that the linewidth of the reflection spectrum decreases upon the increasing distance between the grating strips. This research work will lay a foundation for studying high performance integrated optical sensors in miniature nanostructures.
compound gratings sensitivity sensor figure of merit Chinese Optics Letters
2022, 20(2): 021201
1 中国科学院大学, 北京 100049
2 中国科学院 微电子研究所, 北京 100029
3 新一代通信射频芯片技术北京重点实验室, 北京 100029
4 昂瑞微电子技术有限公司, 北京 100084
采用025 μm GaAs赝配高电子迁移率晶体管(pHEMT)工艺,设计并实现了一种应用于5G通信22~4 GHz频段的高增益共源共栅低噪声放大器(LNA)。通过将并联RC负反馈与共栅接地电容结合,不使用源极电感,实现了宽带高增益的LNA设计。测试结果表明,22~4 GHz频段增益大于24 dB,输出3阶互调(OIP3)为28 dBm,噪声系数(NF)小于078 dB,功耗为190 mW,芯片面积为(810×710) μm2。综合指标(FOM)为144 dB,与同类LNA相比具有一定的优势。
共源共栅 低噪声放大器 输出3阶互调 综合指标 cascode low noise amplifier output third order intermodulation figure of merit