Author Affiliations
Abstract
1 Jinan University, College of Physics & Optoelectronic Engineering, Institute of Nanophotonics, Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Guangzhou, China
2 Tsinghua University, Shenzhen International Graduate School, State Key Laboratory of Chemical Oncogenomics, Shenzhen, China
3 Jinan University, College of Life Science and Technology, Guangzhou, China
Narrowband photodetection is an important measurement technique for material analysis and sensing, for example, nondispersive infrared sensing technique. Both photoactive material engineering and nanophotonic filtering schemes have been explored to realize wavelength-selective photodetection, while most devices have a responsive bandwidth larger than 2% of the operating wavelength, limiting sensing performance. Near-infrared photodetection with a bandwidth of less than 0.2% of the operating wavelength was demonstrated experimentally in Au/Si Schottky nanojunctions. A minimum linewidth of photoelectric response down to 2.6 nm was obtained at a wavelength of 1550 nm by carefully tailing the absorptive and radiative loss in the nanostructures. Multiple functions were achieved on chip with the corrugated Au film, including narrowband resonance, light harvesting for sensing and photodetection, and electrodes for hot electron emission. Benefiting from such a unity integration with in situ photoelectric conversion of the optical sensing signal and the ultranarrowband resonance, self-contained on-chip biosensing via simple intensity interrogation was demonstrated with a limit of detection down to 0.0047% in concentration for glucose solution and 150 ng / mL for rabbit IgG. Promising potential of this technique is expected for the applications in on-site sensing, spectroscopy, spectral imaging, etc.
plasmonics hot electron sensor photodetector spectroscopy Advanced Photonics
2024, 6(2): 026007
江南大学 电子工程系 物联网技术应用教育部工程研究中心， 江苏 无锡 214122
南京邮电大学集成电路科学与工程学院，江苏 南京 210023
氧化镓（Ga2O3）因其合适的禁带宽度（4.5~5.3 eV）在深紫外探测方面具有天然的优势。本文利用常温磁控溅射技术在非晶Ga2O3薄膜表面溅射银纳米颗粒，制备出简易的深紫外光电探测器。结果表明，在5 V偏压下，探测器的暗电流低至94 fA，光暗电流比高达5.9×105，254 nm/365 nm波长抑制比达到1.6×104，探测率为2×1014 Jones（探测率单位），且该探测器在不同电压和不同光强下都能快速且稳定地响应。该探测器优异的深紫外光探测表现与引入的金属银纳米颗粒密切相关。一方面，银纳米颗粒与Ga2O3薄膜间的肖特基势垒的形成有助于减小非晶Ga2O3的暗电流；另一方面，银纳米颗粒的表面等离子振动有助于增强Ga2O3对紫外光的吸收，且紫外光照下银纳米颗粒会产生大量的热载流子使得热电子有足够的能量克服银纳米颗粒与Ga2O3薄膜间的肖特基势垒，使得探测器的光电流增加。本文工作为实现具有低暗电流和高光暗电流比的深紫外光电探测器提供了一种可行的方法。
光电探测器 氧化镓 银纳米颗粒 热电子 肖特基势垒 光学学报
2023, 43(20): 2004003
Author Affiliations
Abstract
1 University of Natural Resources and Life Sciences, Vienna, Department of Bionanosciences, Muthgasse 11, 1190 Vienna, Austria
2 University of Vienna, Department of Physical Chemistry, Währinger Straße 42, 1090 Vienna, Austria
A silver microelectrode with a diameter of 30 µm in an aqueous K2SO4 electrolyte was irradiated with 55 fs and 213 fs laser pulses. This caused the emission of electrons which transiently charged the electrochemical double layer. The two applied pulse durations were significantly shorter than the electron-phonon relaxation time. The laser pulse durations had negligible impact on the emitted charge, which is incompatible with multiphoton emission. On the other hand, the observed dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.
hot electron emission femtosecond laser laser electrochemistry silver electrode Opto-Electronic Advances
2023, 6(6): 220170
1 苏州大学物理科学与技术学院，江苏 苏州 215006
2 苏州大学东吴学院，江苏 苏州 215006
利用铁电薄膜的极化效应和金属微纳结构的表面等离激元非辐射衰减诱导的热电子，提高传统铁电薄膜材料的光电转换效率，在光伏、光催化和光电探测等领域中有广阔的应用前景。采用溶胶-凝胶法制备了大面积均匀的BiFeO3薄膜，并采用电子束热蒸发技术分别在其上下表面沉积Au纳米颗粒，形成了Au/BiFeO3复合薄膜结构。研究结果表明，相较纯BiFeO3薄膜，负载了Au纳米颗粒的复合薄膜在可见光区的吸收明显增强，进而其光电流密度也有所增加。此外，利用铁电薄膜的极化效应对其界面势垒进行调控，从而控制Au纳米颗粒中热电子和BiFeO3薄膜中光生载流子的转移，在两者的协同作用下，实现了对复合薄膜光电流极性的操控。
薄膜 铁电薄膜 表面等离激元 极化效应 热电子 光电流 光学学报
2022, 42(23): 2331001
1 北京工业大学材料与制造学部强场与超快光子学实验室, 北京 100124
2 北京工业大学材料与制造学部教育部跨尺度成型重点实验室, 北京 100124
3 北京空间机电研究所, 北京 100094
为了提升超热电子的准直输运效率,提出了锥口多层靶模型,并通过二维PIC(particle-in-cell)模拟手段研究了强激光与锥口多层靶相互作用过程中超热电子的产生和输运特性。研究结果表明,相比于无锥结构的多层靶,锥口多层靶中输运的超热电子数目更多、能量更高且空间分布也更加集中,发散角被控制在-38°~38°之间的超热电子能量约增加了0.6倍,锥口多层靶能够提升超热电子的准直输运效率。锥口多层靶中超热电子准直输运效率提升的原因主要有三个方面:激光从锥壁上拉出了大量超热电子、锥壁对激光的聚焦作用增强了激光有质动力以及锥顶后方产生了较强的自生磁场分布。本文建立的模型对于提升“快点火”中超热电子的束品质具有重要意义。
激光物理 强激光 锥口多层靶 超热电子输运 中国激光
2021, 48(24): 2401002
渭南师范学院 物理与电气工程学院, 陕西 渭南 714099
根据能带电子输运理论, 对光激发热电子的产生、弛豫、复合过程进行了分析, 并利用蒙特卡罗方法对不同电场中热电子输运的漂移速度瞬变特性进行了模拟。在稳态条件下, 光电导及其相应的光电特性主要决定于复合过程; 而在强电场和高激发状态下, 则主要决定于热电子的行为。实验选用横向型GaAs光电导开关, 在一定的偏置电压条件下输出线性与非线性两种不同模式的电脉冲, 实验结果与理论一致。
热电子 光电导 瞬态输运 hot-electron photoconductance transient transport
表面等离激元诱导热电子光电转换是近年来的研究热点,在光电探测、太阳能电池、光催化反应等方面有着广阔的应用前景。表面等离激元热电子的快速转移和收集可以有效避免弛豫、复合、束缚等过程所引起的能量损失,提高器件的光电转换效率和速度。此外,利用等离激元热电子转移可以打破光电探测波段受限于半导体带隙的瓶颈,为红外光电探测提供有效手段。除贵金属外,重掺杂半导体材料由于可调控的红外表面等离激元共振特性也逐渐引起了人们的广泛关注。介绍了表面等离激元热电子的激发、转移机制及表面等离激元热电子红外光电探测等方面的研究进展,并讨论了该领域存在的问题及挑战,为设计高性能表面等离激元热电子光电转换器件提供了参考。
表面光学 表面等离激元 热电子 红外 光电探测 掺杂半导体 激光与光电子学进展
2019, 56(20): 202403
Author Affiliations
Abstract
1 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
3 Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
4 SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK
5 Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
6 University of Chinese Academy of Sciences, Beijing 100049, China
Absolute instability modes due to secondary scattering of stimulated Raman scattering (SRS) in a large nonuniform plasma are studied theoretically and numerically. The backscattered light of convective SRS can be considered as a pump light with a finite bandwidth. The different frequency components of the backscattered light can be coupled to develop absolute SRS instability near their quarter-critical densities via rescattering process. The absolute SRS mode develops a Langmuir wave with a high phase velocity of about $c/\sqrt{3}$ with $c$ the light speed in vacuum. Given that most electrons are at low velocities in the linear stage, the absolute SRS mode grows with very weak Landau damping. When the interaction evolves into the nonlinear regime, the Langmuir wave can heat abundant electrons up to a few hundred keV via the SRS rescattering. Our theoretical model is validated by particle-in-cell simulations. The absolute instabilities may play a considerable role in the experiments of inertial confinement fusion.
laser plasma interactions stimulated Raman scattering two plasmon decay instability hot electron High Power Laser Science and Engineering
2019, 7(1): 01000e20
东南大学 电子科学与工程学院 信息显示与可视化国际合作实验室, 江苏 南京 210096
为了解决典型宽禁带半导体光电探测器件的工作波段限制材料禁带宽度的问题, 对基于表面等离激元热电子效应的光电晶体管进行了制备和光电性能研究, 提出一种采用重掺杂的硅片作为背栅极、二氧化硅(SiO2)氧化层作为绝缘层, 且能利用等离激元热电子效应的光电晶体管, 有望实现响应光谱的调控。利用热退火方法在绝缘层表面修饰金纳米颗粒, 并结合射频溅射、物理掩模和真空热蒸镀的方法实现了热电子效应铟镓锌氧化物(IGZO)光电晶体管。器件的光学和电学性能测试结果表明：修饰金纳米颗粒的光电晶体管在658 nm红光入射下产生明显的光电响应, 外加90 V栅极偏压时, 光电流提升约为2.2倍。金纳米颗粒修饰的等离激元热电子结构有效调控了该型晶体管的响应光谱范围, 不受材料禁带宽度的限制, 而且晶体管的背栅调控进一步放大光电流, 提高了器件的量子效率。
光电探测 等离激元 热电子 禁带宽度 铟镓锌氧化物 photoelectronic dectection plasmonic hot-electron band gap Indium Gallium Zinc Oxide(IGZO)
