Article
Nanoscience & Nanotechnology
Shuangyin Gao, Yi Huang, Jin Tan, Jianmei Xu, Ling Zhao, Wei Zhou, Zhihong Yang, Jian Sun, Hao Gong
Summary: In this study, highly transparent p-type amorphous Cu-HHTP films were synthesized using electrostatic spinning method and applied as materials for photodetectors. These amorphous films exhibited ultra-high response speed and sensitivity, and maintained stable performance even at high temperatures. Furthermore, a flexible metal-semiconductor-metal photodetector based on p-a-Cu-HHTP was developed, showing excellent mechanical stability and photoresponse, making it suitable for wearable optoelectronics.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Chenchen Song, Mengxue Guan, Yunzhe Jia, Daqiang Chen, Jiyu Xu, Cui Zhang, Sheng Meng
Summary: In this work, the ultrafast dynamics and characteristics of laser-induced structural transformation in graphite are revealed by non-adiabatic quantum dynamic simulations. It is found that graphite undergoes an interlayer compression and sliding stage, followed by a key period of intralayer buckling and interlayer bonding to form an intermediate sp(2)-sp(3) hybrid structure, before completing the full transformation to hexagonal diamond. The process is driven by the cooperation of charge carrier multiplication and selective phonon excitations through electron-phonon interactions, with photoexcited hot electrons playing a key role in introducing in-plane instability in graphite. This work identifies a photoinduced non-adiabatic transition pathway from graphite to diamond and has important implications for designing optically controlled structural phase transition in materials.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Ruiyang Yu, Hui Qiao, Gengcheng Liao, Zongyu Huang, Qiaoliang Bao, Xiang Qi
Summary: In this study, a flexible and highly photoresponsive photoelectrochemical (PEC) photodetector was fabricated. The addition of ATP and NADPH to the electrolyte improved the performance of the photodetector, achieving efficient light-current conversion.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Atreyo Mukherjee, Dragica Vasileska, John Akis, Amir H. Goldan
Summary: Theoretical study on high-field extended-state hole transport processes in amorphous selenium was conducted by modeling the band-transport lattice theory of trigonal selenium. An in-house bulk Monte Carlo algorithm solved the semiclassical Boltzmann transport equation to provide insight into carrier trajectories and relaxation dynamics of non-equilibrium hot holes. The presence of high phonon, disorder, and impurity scattering led to a certain determinism in the otherwise stochastic impact ionization phenomenon in amorphous selenium.
Article
Multidisciplinary Sciences
Linan Zhou, Minhan Lou, Junwei Lucas Bao, Chao Zhang, Jun G. Liu, John Mark P. Martirez, Shu Tian, Lin Yuan, Dayne F. Swearer, Hossein Robatjazi, Emily A. Carter, Peter Nordlander, Naomi J. Halas
Summary: This study demonstrates that the H2-D2 exchange reaction catalyzed by Cu nanoparticles is primarily driven by thermalized hot carriers, with an intriguing intensity-dependent external quantum yield exceeding 100% at high light intensities. Quantum mechanical research suggests that vibrational excitations of the surface Cu-H bond are the likely activation mechanism, supporting the effectiveness of low-energy thermalized hot carriers in photocatalyzing this reaction.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Nanoscience & Nanotechnology
Shiyu Du, Naisen Yu, Xiang Lin, Benkang Liu, Yunfeng Wu, Haiou Li
Summary: A high-performance ultraviolet (UV) photodetector based on amorphous Ga2O3/ZnO nanoarrays on p-GaN film was successfully fabricated. This detector exhibits excellent UV sensing properties in the UV-A/UV-C region with fast response without external bias. The high photosensitivity is attributed to the geometry of the match-like Ga2O3/ZnO nanoarrays and the emergence of built-in field between the amorphous Ga2O3 and ZnO interface. These findings provide a new method to enhance the ZnO/GaN heterostructure for broadband ultraviolet sensing applications.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Kun Ba, Jianlu Wang
Summary: Infrared photodetector based on solution-processed colloidal quantum dots (QDs) has been successfully used in various applications due to its wide-size-tunable bandgap, high quantum confinement potential, and low-cost fabrication. However, the performance of QDs-based photodetectors is limited by low carrier mobility. By depositing QDs solutions on different substrates, such as 2D materials or other QDs, hybrid structures can be engineered to achieve high mobility and light absorbance through synergistic effects. This article focuses on the developments of QDs-based hybrid structures in enhancing the performance of infrared photodetectors and summarizes the current challenges and future development.
Article
Engineering, Electrical & Electronic
Lingxing Xiong, Lei Zhang, Qipu Lv, Tao Li, Wenqing Song, Jiawei Si, Wenhui Zhu, Liancheng Wang
Summary: A bendable and thermally stable solar-blind UV photodetector based on Ni/a-Ga2O3/a-AlN/Cu foil structure has been demonstrated, showing stable UV response characteristics with different bending radii and temperatures, high responsivity, and fast response time, suitable for harsh environments such as high-power bendable electron devices, flame detection, etc.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Seung-Il Kim, Seok-Ki Hyeong, Dong Seop Park, Sang-Hwa Hyun, Ji-Yun Moon, Sangyeob Lee, Tae-Sung Kim, Seoung-Ki Lee, Jae-Hyun Lee, Keun Heo
Summary: This study presents a specially prepared water-soluble amorphous WO3 intermediate layer that effectively protects the graphene surface, leading to improved performance of photodetectors. The surface-protected photodetector showed 1.74 times higher photoresponsivity and faster temporal photoswitching response time compared to the control device.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Sa Cai, Chaolei Zuo, Jiayu Zhang, Hui Liu, Xiaosheng Fang
Summary: A paper-based wearable photodetector is reported, which can simultaneously measure transient light intensity and accumulated light dosage. The photodetector fully utilizes the natural hygroscopicity and softness of paper, showing decent flexibility. This work introduces a new type of wearable photodetector by structure design and material selection, shedding light on more novel works for convenient and practical photodetection.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Optics
Hanchi Xia, Tao Zhang, Yuehui Wang, Yaping Qi, Fan Zhang, Zhenping Wu, Yang Zhang
Summary: Flexible devices have advantages such as conformability, portability, and low cost. Paper-based electronics are lightweight, inexpensive, and biodegradable, making them suitable for disposable electronics. This work proposes a novel configuration of photodetectors using paper as flexible substrates and amorphous Ga2O3 as the active materials. The photoresponse characteristics are systematically investigated, and decent responsivity yield and detectivity are achieved at a low operating voltage. The experiments also demonstrate the device's resistance to twisting and bending deformation. This study presents a candidate strategy for low-cost flexible solar-blind photodetectors using paper substrates and shows their potential for integration with other materials.
CHINESE OPTICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Zhen Ge, Nuo Xu, Yu Zhu, Kai Zhao, Yanfeng Ma, Guanghui Li, Yongsheng Chen
Summary: A flexible hybrid organic photodetector (OPD) was designed and fabricated by integrating organic materials with three-dimensional graphene (3DG) film, enabling light detection from visible to mid-infrared range at room temperature with high responsivity and detection performance. This hybrid detector is compatible with flexible substrates, providing a new approach for flexible electronics.
Article
Chemistry, Multidisciplinary
Huiming Shang, Yunxia Hu, Feng Gao, Mingjin Dai, Shichao Zhang, Shuai Wang, Decai Ouyang, Xinyu Li, Xin Song, Bo Gao, Tianyou Zhai, PingAn Hu
Summary: This study presents a high-gain photodetector based on a vertical InSe/GaSe heterojunction. By inducing carrier recirculation, the device achieves improved optoelectronic performance and sensitivity. The heterojunction also exhibits the ability to detect weaker light, highlighting its potential for various applications.
Article
Chemistry, Multidisciplinary
Teresa Crisci, Piera Maccagnani, Luigi Moretti, Caterina Summonte, Mariano Gioffre, Rita Rizzoli, Maurizio Casalino
Summary: In this work, a vertically illuminated near-infrared photodetector based on graphene layer embedded between crystalline and hydrogenated silicon layers is investigated. The devices show an unexpected increase in thermionic current under near-infrared illumination, attributed to the lowering of the graphene/crystalline silicon Schottky barrier caused by an upward shift in graphene Fermi level induced by charge carriers released from traps at the graphene/amorphous silicon interface. A complex model is presented to reproduce and discuss the experimental observations. The responsivity of the devices reaches a maximum value of 27 mA/W at 1543 nm under an optical power of 8.7 mu W, indicating the potential for developing near-infrared silicon photodetectors for power monitoring applications.
Article
Nanoscience & Nanotechnology
Yu Chang, Linfeng Huang, Yingcai Zhou, Jianyuan Wang, Wei Zhai
Summary: This study proposes a simple and convenient design for a logical color-selective photodetector composed of CdS and Se with a crystalline/amorphous mixed state. The integrated device can accurately identify red, green, and blue light through logical judgment.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Tomoaki Masuzawa, Yoichiro Neo, Hidenori Mimura, Ken Okano, Takatoshi Yamada
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2019)
Article
Materials Science, Multidisciplinary
Shinichi Shikata, Koji Yamaguchi, Akihiko Fujiwara, Yusuke Tamenori, Kazuki Tsuruta, Takatoshi Yamada, Shannon S. Nicley, Ken Haenen, Satoshi Koizumi
DIAMOND AND RELATED MATERIALS
(2020)
Article
Physics, Applied
Joshua D. John, Shun Okano, Apoorva Sharma, Mahfujur Rahaman, Oleksandr Selyshchev, Noritoshi Miyachi, Kunitaka Enomoto, Jun Ochiai, Ichitaro Saito, Georgeta Salvan, Tomoaki Masuzawa, Takatoshi Yamada, Daniel H. C. Chua, Dietrich R. T. Zahn, Ken Okano
APPLIED PHYSICS LETTERS
(2020)
Article
Physics, Applied
Yu Suzuki, Takatoshi Yamada, Michael Hietschold, Ken Okano
JAPANESE JOURNAL OF APPLIED PHYSICS
(2020)
Article
Nanoscience & Nanotechnology
Takatoshi Yamada, Yuki Okigawa, Masataka Hasegawa, Kenji Watanabe, Takashi Taniguchi
Article
Chemistry, Physical
Yuki Okigawa, Tomoaki Masuzawa, Kenji Watanabe, Takashi Taniguchi, Takatoshi Yamada
Summary: The temperature dependence of electrical properties of CVD graphene on HPHT h-BN was evaluated, showing that carrier mobility is influenced by the thickness of HPHT h-BN and can be suppressed by increasing the thickness to mitigate Coulomb scattering. Phonon scattering of graphene and h-BN were found to limit carrier mobility at different temperatures, resulting in different electrical properties.
APPLIED SURFACE SCIENCE
(2021)
Article
Physics, Applied
Joshua D. John, Shun Okano, Apoorva Sharma, Satoru Nishimoto, Noritoshi Miyachi, Kunitaka Enomoto, Jun Ochiai, Ichitaro Saito, Georgeta Salvan, Tomoaki Masuzawa, Takatoshi Yamada, Daniel H. C. Chua, Dietrich R. T. Zahn, Ken Okano
Summary: Superlattice structures have unique electrical and optical properties suitable for applications like quantum cascade lasers and ultra-sensitive photo-detectors, but their fabrication requires specialized techniques like molecular beam epitaxy. Using rotational evaporation, films with alternating layers of amorphous selenium and arsenic selenide were successfully fabricated and their optical properties were investigated using spectroscopic ellipsometry. The models showed distinct absorption energy levels in the multi-layer structure, confirming the transitions between quantum well levels due to the superlattice structure.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Jongbeom Choi, Nana Okimura, Takatoshi Yamada, Yuki Hirata, Naoto Ohtake, Hiroki Akasaka
Summary: Graphene composite with uniformly distributed and less damaged graphene was fabricated by thermal chemical vapor deposition and cold spray, resulting in significantly improved tribological properties. Scanning electron microscope images and Raman spectrum analysis were used to characterize the graphene-coated copper composite, showing enhanced tribological performance compared to pure copper film.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Taku Miyake, Hisaya Nakagawa, Tomoaki Masuzawa, Takatoshi Yamada, Takayuki Nakano, Katsuyuki Takagi, Toru Aoki, Hidenori Mimura
Summary: The radiation detector made of polycrystalline diamond with a boron-doped neutron converter layer is effective in neutron detection, as demonstrated in particle-counting mode using a multichannel analyzer. The fabrication technique involves hot filament chemical vapor deposition, with the detector consisting of an undoped free-standing polycrystalline diamond layer and a B-doped polycrystalline diamond top layer serving as an electrical contact and a converter for neutron-alpha conversion.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Mitsuhiro Okada, Naoka Nagamura, Tarojiro Matsumura, Yasunobu Ando, Anh Khoa Augustin Lu, Naoya Okada, Wen-Hsin Chang, Takeshi Nakanishi, Tetsuo Shimizu, Toshitaka Kubo, Toshifumi Irisawa, Takatoshi Yamada
Summary: This study reports the formation of a monolayer p-n junction in MoS2 using chemical vapor deposition. By optimizing the growth conditions, spatially selective and heavy Nb doping was successfully achieved, resulting in a significant work function difference between the inner and edge regions of the single-crystalline MoS2, leading to n-type and degenerate p-type semiconductor behaviors along with clear rectifying behavior.
Article
Multidisciplinary Sciences
Ryosuke Senga, Yung-Chang Lin, Shigeyuki Morishita, Ryuichi Kato, Takatoshi Yamada, Masataka Hasegawa, Kazu Suenaga
Summary: This study demonstrates the unambiguous isotopic imaging of C-12 carbon atoms in C-13 graphene and the monitoring of their self-diffusion through atomic-level vibrational spectroscopy. The results confirm the high mobility of carbon atoms during growth and annealing via self-diffusion. This imaging technique provides a fundamental methodology for nanoisotope engineering and monitoring.
Article
Instruments & Instrumentation
J. D. John, S. Nishimoto, N. Kadowaki, I. Saito, K. Okano, S. Okano, D. R. T. Zahn, T. Masuzawa, T. Yamada, D. H. C. Chua, T. Ito
Summary: This article presents a method for designing quantum devices using amorphous materials and physical vapor deposition. It shows that the multiplication factor is related to the number of superlattice layers.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Physics, Applied
Moriyoshi Haruyama, Yuki Okigawa, Mitsuhiro Okada, Hideaki Nakajima, Toshiya Okazaki, Hiromitsu Kato, Toshiharu Makino, Takatoshi Yamada
Summary: We investigated the charge-state stabilization of shallow nitrogen-vacancy (NV) centers in (111) diamond using graphene/diamond junctions. Fluorescence stability and charge-state stability were measured on NV centers in both the graphene and graphene-free regions. The results showed that about half of the NV centers in the graphene-free region were unstable, while over 90% of the measured NV centers in the graphene region were stabilized as NV- centers. Graphene/diamond junctions significantly contribute to the charge-state stabilization of shallow NV- centers in (111) diamond.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Tomoaki Masuzawa, Taku Miyake, Hisaya Nakagawa, Takayuki Nakano, Katsuyuki Takagi, Toru Aoki, Hidenori Mimura, Takatoshi Yamada
Summary: In this study, a radiation detector made of polycrystalline diamond was characterized by neutron and alpha particle. The detector consisted of a boron-doped/undoped stacked structure, and the alpha particles were irradiated from the B-doped layer side. The results showed that the formation of the B-doped layer modified the band structure at the B-doped/undoped interface, improving signal hole collection.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Physics, Applied
Takatoshi Yamada, Tomoaki Masuzawa, Yuki Okigawa
Summary: To enhance the carrier mobility and suppress the intrinsic carrier density of graphene on a silicon dioxide substrate, a potassium-doped nano graphene intermediate layer was introduced. Electrical properties of the fabricated graphene field-effect transistors were measured, and the results showed a shift in the Dirac point and increased carrier density and mobility. The ionized potassium atoms in the intermediate layer shielded the electric force from the negatively charged impurities, resulting in improved field-effect mobilities.
APPLIED PHYSICS LETTERS
(2023)
