Article
Chemistry, Multidisciplinary
Luke W. Smith, Jack O. Batey, Jack A. Alexander-Webber, Yu-Chiang Hsieh, Shin- Fung, Tom Albrow-Owen, Harvey E. Beere, Oliver J. Burton, Stephan Hofmann, David A. Ritchie, Michael Kelly, Tse-Ming Chen, Hannah J. Joyce, Charles G. Smith
Summary: This study investigates the insulating states in monolayer graphene grown by chemical vapor deposition (CVD) and wet transferred on Al2O3 without specialized fabrication techniques. The results show the existence of insulating properties and the opening of an energy gap induced by the magnetic field in a graphene device with a bottleneck. A locally high-quality region within the bottleneck dominates transport and causes the device to behave as an insulating tunnel junction. The use of wet transfer fabrication techniques and multiplexing demonstrates the convenience of these scalable and reasonably simple methods for finding high-quality devices for fundamental physics research and functional properties.
Article
Chemistry, Physical
Zixuan Zhao, Can Zou, E. Zhou, Qing Liu, Kai Chen, Xingfu Wang, Longfei He, Fangliang Gao, Shuti Li
Summary: Interface engineering improves the performance of graphene-based photodetectors. A graphene/GaAs heterojunction photodetector was fabricated and by inserting an Al2O3 tunneling layer, its performance was enhanced through direct tunneling (DT) and Fowler-Nordheim tunneling (FNT). The thickness of the tunneling layer was found to significantly affect the photodetector's performance. Compared with a graphene/GaAs photodetector, the graphene/Al2O3(2 nm)/GaAs photodetector showed improved responsivity, detectivity, and external quantum efficiency, achieving values of 0.80 A/W, 3.02 x 1011 Jones, and 306% respectively under 1 mW/cm2 light intensity at 2 V bias. The photodetector also exhibited a fast response with rise/decay times of 3 ms/8.6 ms. The improved performance of the photodetector was mainly attributed to the effective modification of the interface state by the Al2O3 tunneling layer and the influence of the two tunneling mechanisms based on DT and FNT.
SURFACES AND INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Inchul Choi, Nae Bong Jeong, Minjeong Kim, Jaeho Yu, Hyun-Jong Chung
Summary: The current mechanism of the graphene-WS2 junction evolves from thermionic emission to field emission as the height decreases with the accumulation of electrons, and also changes with increasing temperature due to the decrease in WS2 thickness. The alignment of the Fermi level of graphene to the Dirac point may cause a kink in the I-D-V-D curves.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jun-Ho Lee, Inchul Choi, Nae Bong Jeong, Minjeong Kim, Jaeho Yu, Sung Ho Jhang, Hyun-Jong Chung
Summary: This study investigates the tunneling of graphene/insulator/metal heterojunctions by revising the Tsu-Esaki model and direct tunneling current. The study shows that the revised equations for both tunneling currents are proportional to V-3, which is due to the linear dispersion of graphene. A simulation tool is developed using MATLAB with the revised tunneling equations. The device performance of the field-emission barristor is optimized by engineering the barrier height and thickness, improving the delay time, cut-off frequency, and power-delay product.
Article
Computer Science, Information Systems
Giorgiana-Catalina Ilie (chiranu), Cristian Tudoran, Otilia Neagoe, Florin Draghici, Gheorghe Brezeanu
Summary: This paper describes a nonvolatile switch based on n-type floating-gate transistors, where switch states are programmed through memory cell floating-gate voltage. The advantages include higher levels than the application supply, reduced power consumption, and on-state resistance not depending on supply voltage, making it suitable for low-voltage applications.
Article
Multidisciplinary Sciences
Lei Tong, Meng Peng, Peisong Wu, Xinyu Huang, Zheng Li, Zhuiri Peng, Runfeng Lin, Qiaodong Sun, Yaxi Shen, Xuefeng Zhu, Peng Wang, Jianbin Xu, Lei Ye
Summary: The research utilizes MoTe2/h-BN/MoTe2/h-BN heterostructure to achieve hole-dominated Fowler-Nordheim quantum tunneling transport in both on and off states, achieving high detectivity and fast response in photodetection performance, promising superior imaging capabilities.
Article
Chemistry, Physical
Qing Liu, Weidong Song, Xingfu Wang, Zixuan Zhao, Can Zhou, Kai Chen, Shaobing Zhan, Fangliang Gao, Shuti Li
Summary: This study reports a quantum mechanical Fowler-Nordheim tunneling (FNT) mechanism in a graphene 2D/GaN 3D ultraviolet (UV) photodetector with an atomic layer deposition Al2O3 tunneling layer, and investigates the conversion between direct tunneling (DT) and FNT. Under reverse bias (< -0.253 V), the high-speed photogenerated carriers overcome the thin insulator layer through FNT, resulting in impact ionization and multiplication of photocurrent. The photodetector exhibits excellent photoresponse performances under weak light conditions, including high responsivity (122.57 A/W), ultrahigh specific detectivity (5.63 x 10(14) Jones), and high sensitivity (1.29 x 10(7)%), indicating its exceptional weak light detection ability. This work presents a novel approach to fabricate high-performance optoelectronic devices utilizing the FNT tunneling mechanism.
Article
Chemistry, Multidisciplinary
Zongqi Bai, Yang Xiao, Qing Luo, Miaomiao Li, Gang Peng, Zhihong Zhu, Fang Luo, Mengjian Zhu, Shiqiao Qin, Kostya Novoselov
Summary: The emergence of two-dimensional materials has led to important applications in electronic and optoelectronic devices. However, there are limitations such as low ON/OFF ratio and Schottky barrier formation. In this study, highly tunable field-effect tunneling transistors based on vertical graphene-WS2-graphene heterostructures were demonstrated, overcoming these limitations and achieving low off-state current, high ON/OFF ratio, and controllable carrier transport polarity.
Article
Chemistry, Physical
Jun -Dar Hwang, Cyuan-Sin Li, Chin -Yang Chang
Summary: With the development of MIS field-effect transistors, the use of MgO/SiOx stack dielectrics can effectively suppress the gate leakage current and improve the performance of MIS diodes. The stack reduces the oxygen vacancy of MgO, decreases the fixed oxide charge and interface trap charge density, and enhances the rectification ratio. The barrier height also increases in the stack, allowing for Fowler-Nordheim tunneling at high reverse-bias voltage and direct tunneling at low reverse-bias voltages.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Filippo Giubileo, Enver Faella, Aniello Pelella, Arun Kumar, Daniele Capista, Maurizio Passacantando, Sang Sub Kim, Antonio Di Bartolomeo
Summary: The field emission properties of SnO2 nanofiber networks have been systematically investigated, demonstrating a field emission current at low electric fields, and a maximum field enhancement factor at a separation distance of 200 nm. The emission from a single nanofiber shows current saturation.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Maryam Sadat Amiri Naeini, Pierre Berini
Summary: Plasmonic hot carriers on metal-oxide-semiconductor (MOS) diodes have the potential for innovative optoelectronics on technologically important structures. The photoresponse of MOS diodes is reported due to the tunneling of hot holes created in the metal contact via the absorption of infrared surface plasmons. The theoretical modeling and measurements show excellent agreement, allowing for the extraction of tunneling effective masses in the oxide of the MOS structures.
Article
Chemistry, Multidisciplinary
Yitong Wang, Wenbo Peng, Zihao Huang, Danyang Huang, Wanli Xie, Fangpei Li, Yongning He
Summary: The piezo-phototronic effect is used to modulate the dynamics of photo-generated carriers by utilizing external-strain-induced piezoelectric charges. In this study, the piezo-phototronic effect on a PEDOT:PSS/Al2O3/n-ZnO tri-layer MOS tunneling junction is systematically investigated. It is found that the negative piezo-charges reduce the photoresponsivity to 365 nm laser illumination, while unexpectedly, the similar phenomenon is observed when utilizing the positive piezo-charges. The in-depth working mechanisms are analyzed, revealing that strain induced piezo-charges can adjust the barrier height and width of the intermediate oxide layer, thereby efficiently modulating the tunneling effect and controlling the MOS tunneling junction's photo-carriers dynamic and corresponding photoresponses.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Feng Gao, Xin Zhang, Biying Tan, Shichao Zhang, Jia Zhang, Dechang Jia, Yu Zhou, PingAn Hu
Summary: The authors have developed an optoelectronic memory based on SnS2/h-BN/graphene heterostructure with an extremely low photo-generated hole tunneling barrier. This floating gate memory exhibits high switching ratio and large memory window range, capable of achieving multilevel storage states under low power light pulses.
Article
Nanoscience & Nanotechnology
Masahiro Nakayama, Kentaro Kajimoto, Tomoki Misaka, Naoya Mishima, Takashi Yamada, Hiroshi Ohoyama, Takuya Matsumoto
Summary: The alignment of molecular electronic levels in a molecular multilayer is crucial for desired functions. This study utilized a new testing method to probe the energy-level alignment in an organic multilayer. The results showed weak coupling between layers at low voltage and significant loss of electrostatic energy at high voltage.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Qing Liu, Jiang Shi, Weidong Song, Xingfu Wang, Longfei He, Shaobin Zhan, Fangliang Gao, Shuti Li
Summary: In this study, a high-precision ultraviolet (UV) position-sensitive detector (PSD) constructed by graphene/GaN heterojunction is proposed for the first time. The device utilizes the Fowler-Nordheim tunneling mechanism to improve performance and can determine the position of the UV light spot under weak light power. It exhibits high precision, excellent weak light detection capability, and good linearity without power supply.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)