Article
Optics
Abdulrahman Mesgin Balow, Mehdi Khatir, Nasrin Amiri
Summary: A novel plasmonic nano-antenna array with stepped strips at the edge of contact electrodes is proposed for improved performance in optical-to-terahertz conversion efficiency. Simulations show that this photoconductive antenna can efficiently transmit light to LT GaAs substrate under an optical pump power of 50 mW without any reflection, generating an optical current of 215 nA and achieving broadband terahertz detection over the 0.1-8 THz frequency range with significant improvement over previous structures.
Article
Materials Science, Multidisciplinary
S. Candussio, S. Bernreuter, T. Rockinger, K. Watanabe, T. Taniguchi, J. Eroms, I. A. Dmitriev, D. Weiss, S. D. Ganichev
Summary: This article reports on the observation of circular transversal terahertz photoconductivity in monolayer graphene supplied by a back gate. The photoconductivity response is caused by free carrier absorption and reverses its sign when the radiation helicity is switched. Additionally, the observation of a dc Hall effect suggests the breaking of time inversion symmetry induced by circularly polarized terahertz radiation in the absence of a magnetic field.
Article
Chemistry, Multidisciplinary
Abdelsalam Rawashdeh, Aaron Wildenborg, Eric Liu, Zhi Gao, David A. Czaplewski, Hongwei Qu, Jae Yong Suh, Ankun Yang
Summary: Researchers have developed a scalable method for fabricating sodium (Na) nanostructures with ultralow optical loss and tunable surface plasmon polariton (SPP) modes spanning visible to NIR. They have also addressed the reactivity challenges of Na through a simple encapsulation strategy, enabling the stable existence of Na nanostructures for over two months. Sodium, as a low-cost and low-loss plasmonic material, offers a competitive option for nanophotonic devices and plasmon-enhanced applications.
Article
Physics, Applied
Zheng Feng, Hongsong Qiu, Dacheng Wang, Caihong Zhang, Song Sun, Biaobing Jin, Wei Tan
Summary: Despite the mature technology of microwave and infrared sources, there has been a lag in sources that can work well across the terahertz range, known as the THz gap. The emergence of a novel spintronic THz emitter (STE) has shown unique features and advantages, with the potential to develop new applications. Multidisciplinary efforts have been made to improve the performance of STE, which may inspire a variety of real-world applications in the near future.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Zhangqiang Yang, Xiangyu Xu, Kelvin H. L. Zhang, Ye Yang
Summary: In this study, the photoconductivity of gallium oxide thin films at different temperatures was investigated using time-resolved terahertz spectroscopy. The findings suggest that electron-hole recombination in the conduction band is determined by directional electron drift instead of random diffusion. The electron mobilities measured in response to the terahertz field are significantly higher than the previously reported Hall mobilities, indicating that the electron drift is immune from scattering with macroscopic defects.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Seongin Hong, Nicolo Zagni, Sooho Choo, Na Liu, Seungho Baek, Arindam Bala, Hocheon Yoo, Byung Ha Kang, Hyun Jae Kim, Hyung Joong Yun, Muhammad Ashraful Alam, Sunkook Kim
Summary: Various large-area growth methods have been developed for two-dimensional transition metal dichalcogenides, but have not been used for synthesizing active pixel image sensors. An active pixel image sensor array with bilayer MoS2 film was successfully prepared and exhibited high photoresponsivity. The main mechanism for the high photoresponsivity of bilayer MoS2 phototransistors is attributed to a photo-gating effect by holes trapped at subgap states.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Qiaoxia Xing, Chaoyu Song, Chong Wang, Yuangang Xie, Shenyang Huang, Fanjie Wang, Yuchen Lei, Xiang Yuan, Cheng Zhang, Lei Mu, Yuan Huang, Faxian Xiu, Hugen Yan
Summary: This study demonstrates strong terahertz plasmons in graphite thin films with dramatic tunability by even a moderate temperature change or an in situ bias voltage, and reveals that massive electrons and massless Dirac holes make comparable contributions to the plasmon response through magnetoplasmon studies. It not only sets up a platform for further exploration of two-component plasmas, but also opens an avenue for terahertz modulation through electrical bias or all-optical means.
PHYSICAL REVIEW LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Qi Song, Yu Zhou, Yifei Wang, Feilong Gao, Jiatong Wang, Min Zhang, Yiran Wang, Bingyuan Zhang, Peiguang Yan, Bo Dong
Summary: Due to the low photon energy in the relevant frequency band, the development of 6G technology is limited by the lack of materials that can directly excite carriers and high-performance large-area detectors. Additionally, the integration of 6G communication and Internet of Things technology in flexible detectors has great potential for application in optoelectronic devices. A large-area flexible thin layer terahertz detector is designed to combine excellent optoelectronic performance and the localized surface plasmon effect in a sub-wavelength structure detector. The device demonstrates high performance at room temperature with good noise equivalent power and photoresponsivity at 0.28 THz, making it advantageous for flexible 6G detector applications.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Optics
Wang-Chien Chen, Chia-Wei Chang, Shang-Hua Yang
Summary: THz photoconductive emitters based on III-V materials have shown excellent performance, but their incompatibility with the CMOS fabrication process and challenging growth conditions limit large-scale production. To overcome this, we propose the use of GeSn alloy as a CMOS-compatible photoconductive material. GeSn exhibits high mobility and absorption coefficient, enabling fast photocurrent generation for THz radiation. This GeSn THz emitter offers a bandwidth of over 2 THz and a signal-to-noise ratio of 40 dB, showing potential for mass-producible, cost-effective THz integrated systems with CMOS technology.
Article
Physics, Applied
Weien Lai, Qing Zhu, Gen Liu, Guanghua Shi, Yichen Gan, Abbas Amini, Chun Cheng
Summary: The study proposes a broadband and large-depth THz modulator based on silicon/silver nanoparticle arrays, which can achieve broadband modulation within the frequency range of 0.2-2.0 THz with a large modulation depth of 91.2% under a NIR light intensity of 1.77 W cm(-2).
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Yangyang Zhao, Yicong Chen, Guofu Zhang, Runze Zhan, Juncong She, Shaozhi Deng, Jun Chen
Summary: The research focuses on the application of large-area indium-doped zinc oxide nanowire arrays in flat-panel X-ray sources, aiming to enhance emission current by altering the conductivity and lattice structure. Results show that the high emission current is mainly attributed to the high crystallinity and conductivity change induced by the indium dopants.
Article
Optics
Mohammad Javad Mohammad-Zamani
Summary: The proposed terahertz photomixer features an innovative design of recessed contact electrodes, significantly enhancing optical absorption and terahertz photo current, leading to an increase in terahertz power by over three orders of magnitude. Additionally, the emitter has a wide frequency tuning capability ranging from 0.1-5 THz.
Article
Chemistry, Multidisciplinary
Hong Su, Zesong Zheng, Zhisheng Yu, Shiping Feng, Huiting Lan, Shixing Wang, Min Zhang, Ling Li, Huawei Liang
Summary: In this paper, a broadband terahertz modulator based on a high-resistance silicon substrate and a layer-dependent PtSe2 nanofilm is proposed and experimentally demonstrated. The results show that a 3-layer PtSe2 nanofilm has better surface photoconductivity in the terahertz band and exhibits a higher plasma frequency and a lower scattering time compared to films with more layers. By utilizing terahertz time-domain spectroscopy, it is shown that the 3-layer PtSe2 film achieves broadband amplitude modulation with a modulation depth of 50.9% at a specific pump density. This work confirms the suitability of PtSe2 nanofilm devices for terahertz modulation.
Article
Chemistry, Physical
Xiaoqing Zhu, Bo Wang
Summary: In this paper, a broadband metamaterial absorber consisting of the doped silicon substrate and the square array of doped silicon covered by a SU-8 layer is presented. The target structure achieves an average absorption of 94.42% in the studied frequency range (0.5-8 THz). In particular, the structure exceeds 90% absorption in the frequency range of 1.44-8 THz, which is a significant increase in bandwidth relative to reported devices of the same type. The proposed structure has characteristics such as polarization insensitivity, wide-angle absorption, and good process tolerance, making it advantageous for applications in THz shielding, cloaking, sensing, and energy harvesting.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Yucheng Liu, Weihao Liu, Qika Jia, Baogen Sun, Jun Chen
Summary: This article introduces an enhanced terahertz laser diode (TLD) that uses multiple field-emitter cathodes with coupled cavities, resulting in improved performance and accessibility. The method reduces the required electric field intensity and emission current density, making it easier to manufacture and widening its range of applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
