Article
Optics
Yuxuan Li, Xiaobin Liu, Xuetong Li, Lanxuan Zhang, Yingzhi Li, Baisong Chen, Zihao Zhi, Fengli Gao, Xueyan Li, Pengfei Guo, Xianshu Luo, Guoqiang Lo, Junfeng Song
Summary: In this study, an integrated waveguide-based Ge-on-Si APD with a lateral separate absorption charge multiplication (SACM) structure is proposed to improve detection sensitivity. The device operates at low bias voltage and demonstrates low dark current and practical dark count rate at room temperature. Theoretical single photon detection efficiency is also achieved, reducing the dependence on low-temperature working environment.
OPTICS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Iksoo Park, Seonghwan Shin, Jungsik Kim, Bo Jin, Jeong-Soo Lee
Summary: The study investigated the effects of carbon incorporation on the thermal stability and electrical characteristics of Ti/TiO2/n-Ge contacts, demonstrating that carbon doping can improve contact stability and suppress the decomposition of the interfacial TiO2 layer along with the diffusion of oxygen. Carbon incorporation can maintain relatively stable contact characteristics at high temperatures.
Article
Engineering, Electrical & Electronic
Michael Oehme, Mathias Kaschel, Steffen Epple, Maurice Wanitzek, Zili Yu, Daniel Schwarz, Ann-Christin Kollner, Joachim N. Burghartz, Jorg Schulze
Summary: This paper presents a near-infrared Ge-on-Si camera with backside illumination, showcasing high fill-factor and linear photocurrent characteristics. By operating the Ge-on-Si detectors under zero bias, dark current is minimized and high signal-to-noise ratio and optical responsivity are achieved.
IEEE SENSORS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Bongkwon Son, Yiding Lin, Kwang Hong Lee, Joe Margetis, David Kohen, John Tolle, Chuan Seng Tan
Summary: This work demonstrates metal-semiconductor-metal photodetectors on the Ge0.91Sn0.09-on-insulator (GeSnOI) platform, with the potential to detect wavelengths beyond 2,200 nm, low dark current density, and high bandwidth.
IEEE PHOTONICS JOURNAL
(2022)
Article
Optics
Qiwei Xu, Jun Hu, Xihua Wang
Summary: Silicon photonics technology has experienced explosive growth in the past twenty years, revolutionizing various fields such as high-speed optical interconnects in data centers. A comprehensive study comparing three materials for photodetectors integrated with waveguides in silicon photonics has been conducted to predict the future performances of Indium Gallium Arsenide (InGaAs) and Colloidal Quantum Dot (CQD) photodetectors.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Cihyun Kim, Tae Jin Yoo, Min Gyu Kwon, Kyoung Eun Chang, Hyeon Jun Hwang, Byoung Hun Lee
Summary: The structure of a gate-controlled graphene/germanium hybrid photodetector was optimized by splitting the active region, resulting in significantly improved infrared detection capability.
Article
Materials Science, Multidisciplinary
Shaoying Ke, Jiahui Li, Jie Wang, Jinrong Zhou, Zhiwei Huang, Jinlong Jiao, Ruoyun Ji, Songyan Chen
Summary: By comparing Ge/SOI wafer bonding with amorphous Ge and polycrystalline Ge interlayers, it is found that polycrystalline Ge can better improve the quality of Ge film as it serves as both a perfect lattice blocking layer and a gas transporter to absorb bubbles, helping to eliminate bubbles and dislocations.
Article
Chemistry, Multidisciplinary
Dmitry Averyanov, Ivan S. Sokolov, Alexander N. Taldenkov, Oleg E. Parfenov, Andrey M. Tokmachev, Vyacheslav G. Storchak
Summary: 2D magnetic materials are at the forefront of magnetism research, exhibiting unconventional phases and properties controlled by external stimuli. This study reports 2D magnetic phases of Eu on the Ge(110) surface, with different surface densities of Eu atoms. The phases exhibit in-plane magnetic ordering at low temperatures, with a strong dependence of the effective magnetic transition temperature on weak magnetic fields. The study suggests that a variety of substrates can host submonolayer 2D magnetic phases.
Article
Optics
Yufei Liu, Jialinag Sun, Ruogu Song, Xinyu Li, Jinyu Wang, Shuxiao Wang, Yijia Yu, Wencheng Yue, Yan Cai, Mingbin Yu
Summary: This study demonstrates a Ge electro-absorption modulator (EAM) in the L band with a 3 dB electro-optical bandwidth beyond 67 GHz. The device achieves a data rate of over 80 Gbps for non-return-to-zero on-off keying (NRZ-OOK) modulation at a voltage swing of 2.3V(pp) and a wavelength of 1605 nm. The introduction of an annealing process after CMP is proven to increase the mean static extinction ratio of the EAM, confirming its manufacturability.
Article
Engineering, Electrical & Electronic
Yiding Lin, Bongkwon Son, Kwang Hong Lee, Jurgen Michel, Chuan Seng Tan
Summary: This study demonstrates a vertical p-i-n Ge photodiode with remarkably low dark current on a high-quality GOI substrate. By reducing threading dislocation density in Ge and improving device fabrication, the photodiodes show high responsivity and specific detectivity at specific wavelengths and voltages. These findings pave the way for advanced imaging and sensing applications in PICs at near-infrared and short-wave infrared wavelengths.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Optics
I. A. Fischer, M. Brehm, M. De Seta, G. Isella, D. J. Paul, M. Virgilio, G. Capellini
Summary: The integration of Ge on Si for photonics applications has reached a high level of maturity, with Ge photodetectors and Si/Ge heterostructure multiple quantum-well photodiodes being widely used. The development of high-quality material growth and integration has led to a broad field of photonic device research based on Si/Ge heterostructures, enabling applications ranging from quantum cascade lasers to sensors.
Article
Optics
Xiao Hu, Dingyi Wu, Ye Liu, Min Liu, Daigao Chen, Lei Wang, Xi Xiao, Shaohua Yu
Summary: Based on the commercial silicon photonics (SiPh) process platform, a germanium-silicon (Ge-Si) photodetector (PD) with a flat 3 dB bandwidth of 80 GHz is experimentally demonstrated, achieving an exceptional bandwidth performance by using the gain peaking technique. The peaked Ge-Si PD exhibits high-speed large signal reception capability and shows improved transmitter dispersion eye closure quaternary (TDECQ) penalties compared to the un-peaked PD. Additionally, it demonstrates comparable bit error rate (BER) performance to a 70 GHz Finisar PD, making it a potential solution for supporting high-speed optical receivers.
Article
Engineering, Electrical & Electronic
Kahtan Adnan Hussain, Ghusoon M. Ali, Aimen Boubaker, Adel Kalboussi
Summary: This work presents the fabrication and characterization of a p-type organic metal-semiconductor-metal (MSM) Schottky barrier visible photodetector. The pentacene thin film was deposited on an n-Si <111> substrate using thermal vacuum deposition. The properties and performance of the photodetector were analyzed, and the results showed that the fabricated organic MSM contact has potential applications in visible photodiode devices.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Physics, Multidisciplinary
Zhiwei Huang, Shaoying Ke, Jinrong Zhou, Yimo Zhao, Wei Huang, Songyan Chen, Cheng Li
Summary: A near-infrared germanium (Ge) Schottky photodetector with an ultrathin silicon barrier enhancement layer on Si or silicon-on-insulator (SOI) substrates is proposed and fabricated in this study. The ITO/Si cap/Ge Schottky junctions formed without intentional doping process for the Ge epilayer exhibit low dark current densities and high optical responsivity. These CMOS compatible Si (or SOI)-based ITO/Si cap/Ge Schottky PDs are useful for efficiently detecting near-infrared wavelengths.
Article
Materials Science, Multidisciplinary
Ziqiang Zhao, Cheol-Min Lim, Chong Pei Ho, Kei Sumita, Yuto Miyatake, Kasidit Toprasertpong, Shinichi Takagi, Mitsuru Takenaka
Summary: This study investigates the optical losses in Ge waveguides on a GeOI wafer fabricated using Smart-cut. The high optical loss is mainly attributed to holes in Ge films caused by crystal defects formed during hydrogen ion implantation. The research demonstrates that the carrier concentration profile in remaining Ge films depends on the hydrogen ion implantation energy and initial background doping concentration of Ge wafers.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Chemistry, Multidisciplinary
Sifan Li, Mei-Er Pam, Yesheng Li, Li Chen, Yu-Chieh Chien, Xuanyao Fong, Dongzhi Chi, Kah-Wee Ang
Summary: The study demonstrates a memristor crossbar array using large-scale hafnium diselenide thin films and a metal-assisted transfer technique, showing low switching voltage and energy, high recognition accuracy, and power efficiency. Hardware multiply-and-accumulate operation and programmable kernel-based image processing were successfully showcased.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Mei Er Pam, Sifan Li, Tong Su, Yu-Chieh Chien, Yesheng Li, Yee Sin Ang, Kah-Wee Ang
Summary: This study demonstrates a facile approach to transform an inactive rhenium disulfide (ReS2) into an effective switching material through interfacial modulation induced by molybdenum-irradiation (Mo-i) doping. The results show that ReS2 of various thicknesses can be switchable by modulating the Mo-irradiation period. The fabricated device exhibits bipolar non-volatile switching, programmable multilevel resistance states, and long-term synaptic plasticity. Additionally, it achieves a high MNIST learning accuracy of 91% under a non-identical pulse train.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yesheng Li, Shuai Chen, Zhigen Yu, Sifan Li, Yao Xiong, Mer-Er Pam, Yong-Wei Zhang, Koh-Wee Ang
Summary: This paper presents a low-voltage memristor array based on an ultrathin PdSeOx/PdSe2 heterostructure switching medium, which solves the problem of random ion transport in traditional memristors, achieving remarkable uniform switching with low variability. Convolutional image processing with high recognition accuracy was also achieved by using various crossbar kernels.
ADVANCED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Bochang Li, Wei Wei, Li Luo, Ming Gao, Zhi Gen Yu, Sifan Li, Kah-Wee Ang, Chunxiang Zhu
Summary: A novel electrochemical metallization memristor based on solution-processed Pt/CuI/Cu structure is proposed and demonstrated in this work. It has high resistance switching ratio and low power consumption, enabling Boolean logic operations and image encryption and decryption.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Multidisciplinary Sciences
Viacheslav Sorkin, Hangbo Zhou, Zhi Gen Yu, Kah-Wee Ang, Yong-Wei Zhang
Summary: In this study, the effects of different types, locations, and densities of point defects in monolayer MoS2 on the electronic structures and Schottky barrier heights (SBH) of Au/MoS2 heterojunction are investigated using DFT calculations. The results show that the SBH of monolayer MoS2 with defects is universally higher than that of the defect-free counterpart. Specifically, S divacancy and Mo-S antisite defects have a larger effect on increasing the SBH compared to S monovacancy. Defects located in the inner sublayer of MoS2 also have a larger impact on the SBH than those in the outer sublayer. Increasing defect density leads to a higher SBH. These findings provide practical guidelines for controlling and optimizing the SBH in Au/MoS2 heterojunctions through defect engineering.
SCIENTIFIC REPORTS
(2022)
Review
Chemistry, Multidisciplinary
Jun-young Kim, Xin Ju, Kah-Wee Ang, Dongzhi Chi
Summary: Two-dimensional materials have attracted attention for their potential in scientific breakthroughs and technological innovations. The integration of 2DMs on Si CMOS platform or flexible electronics has gained interest for applications such as back-end-of-line transistors, memory devices/ selectors, and sensors. The successful transfer of 2DM layers from growth substrate to Si is crucial for these applications, and various transfer methods leveraging van der Waals transfer capability have been developed. This review surveys and compares these transfer methods, focusing on 2D TMDC film transfer and 2DM template-assisted van der Waals growth/transfer of non-2D thin films.
Article
Chemistry, Multidisciplinary
Yu-Chieh Chien, Heng Xiang, Yufei Shi, Ngoc Thanh Duong, Sifan Li, Kah-Wee Ang
Summary: The study demonstrates a hafnium oxide-based ferroelectric encoder for temporal-efficient information processing in SNN. This high-performance ferroelectric encoder features superior switching efficiency and robust ferroelectric response, achieving a broad dynamic range.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Heng Xiang, Yu-Chieh Chien, Lingqi Li, Haofei Zheng, Sifan Li, Ngoc Thanh Duong, Yufei Shi, Kah-Wee Ang
Summary: This study demonstrates the capabilities of an integrated ferroelectric HfO2 and 2D MoS2 channel FeFET for achieving high-performance 4-bit per cell memory and low variation and power consumption synapses. The device retains the ability to implement diverse learning rules and accurately recognizes MNIST handwritten digits with over 94% accuracy using online training mode. These results highlight the potential of FeFET-based in-memory computing for future neuromorphic computing applications.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yu-Chieh Chien, Heng Xiang, Jianze Wang, Yufei Shi, Xuanyao Fong, Kah-Wee Ang
Summary: By harnessing the physically unclonable properties, true random number generators (TRNGs) can generate random bitstreams that are cryptographically secured, alleviating security concerns. However, conventional hardware often shows predictable patterns susceptible to machine learning attacks. This paper presents a low-power self-corrected TRNG based on molybdenum disulfide ferroelectric field-effect transistors, which exhibits enhanced stochastic variability and passes machine learning attacks, as well as statistical tests.
Article
Automation & Control Systems
Ngoc Thanh Duong, Yu-Chieh Chien, Heng Xiang, Sifan Li, Haofei Zheng, Yufei Shi, Kah-Wee Ang
Summary: A 1D array of Fe-FET based on alpha-In2Se3 channel is demonstrated, which exhibits volatile memory effect and is capable of implementing various RC systems. It achieves high accuracy in image classification and accurate forecasting of real-life chaotic systems such as weather.
ADVANCED INTELLIGENT SYSTEMS
(2023)
Article
Chemistry, Multidisciplinary
Zhengjin Weng, Haofei Zheng, Wei Lei, Helong Jiang, Kah-Wee Ang, Zhiwei Zhao
Summary: This study demonstrates the successful fabrication of high-yield, high-performance, and uniform memristors using a single-crystalline few-layered manganese phosphorus trisulfide (MnPS3) as a resistive switching medium. The memristors exhibit desired characteristics for neuromorphic computing and achieve a high accuracy of 95.15% in supervised learning using the MNIST handwritten recognition dataset. This research is significant for experimental studies on memristors.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Yangwu Wu, Ngoc Thanh Duong, Yu-Chieh Chien, Song Liu, Kah-Wee Ang
Summary: Neuromorphic computing, specifically reservoir computing (RC), is an effective approach for time-series analysis and forecasting in economics and engineering. In this study, a synapse device based on CuInP2S6 (CIPS) material is demonstrated, achieving synaptic performance emulation and temporal dynamics under electrical stimulation. The migration of Cu+ ions in CIPS is controlled, and the device exhibits low normalized root mean square errors (NRMSE) for various tasks, highlighting the potential of CIPS for real-time signal processing and expanding applications in neuromorphic computing.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Xinke Liu, Yuheng Lin, Zhichen Lin, Jiangchuan Wang, Ziyue Zhang, Yugeng Li, Xiaohua Li, Deliang Zhu, Kah-Wee Ang, Ming Fang, Wangying Xu, Qi Wang, Wenjie Yu, Qiang Liu, Shuangwu Huang
Summary: The use of plasmonic structure enhances the performance of MoS2-based devices, and in this study, a plasmonic-enhanced few-layer MoS2 photodetector was successfully prepared on a GaN substrate, demonstrating high responsivity and low noise.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Review
Chemistry, Physical
Heng Xiang, Yu-Chieh Chien, Yufei Shi, Kah-Wee Ang
Summary: The security of Internet-of-Things (IoT) is crucial in various aspects such as device-to-device communication, sensing and actuating, and information exchange. Conventional cryptographic algorithms and silicon-based security primitives are constantly challenged by evolving attack methods, thus the implementation of hardware security using 2D materials is worth exploring. This review summarizes the research progress in 2D material-based true random number generators (TRNGs), physical unclonable functions (PUFs), and other security applications, and discusses entropy sources, reliability, circuit, and machine learning modeling attacks on TRNGs and PUFs.
Review
Engineering, Electrical & Electronic
Li Chen, Mei Er Pam, Sifan Li, Kah-Wee Ang
Summary: Ferroelectric memory devices based on 2D materials are recognized as promising building blocks for brain-like neuromorphic computing due to their fast-switching speed and ultra-low power consumption. The unique properties of 2D materials and their high compatibility with existing technology make them potential candidates for extending state-of-the-art ferroelectric memory technology into atomic-thin scale.
NEUROMORPHIC COMPUTING AND ENGINEERING
(2022)
