Article
Engineering, Electrical & Electronic
Lin-Qing Zhang, Zhi-Yan Wu, Peng-Fei Wang
Summary: In this paper, a novel semi-floating gate (SFG) AlGaN/GaN HEMT with 20 nm Al2O3 as the control gate capacitance for normally-off operation was reported. This technique avoids the gate recess process which may damage the 2DEG channel and allows for programming of the threshold voltage (V-th) by adjusting the control gate voltage (V-CGP). Experimental results demonstrate the successful fabrication of E-mode AlGaN/GaN HEMTs using this technique.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Ming Yang, Qizheng Ji, Yuanyuan Wang, Xiaofeng Hu, Qingyun Yuan, Xiaoning Liu, Jihao He, Ruojue Wang, Li Zhou, Jingbo Xiao, Fei Mei, Xiao Liu, Zhengyu Wang, Chao Zhang, Jiapeng Wu, Yujing Wu, Yingqian Liu, Zhengang Cui
Summary: Gate-channel electron low-field transport characteristic in AlGaN/GaN HFETs was investigated using measured current-voltage and capacitance-voltage curves. It was found that the HFET with drain Schottky contact exhibits a larger electron mobility compared to the traditional drain Ohmic contact. The difference in transport characteristics is attributed to the polarization charge distributions near the drain electrode.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Physics, Applied
Duong Dai Nguyen, Takehiro Isoda, Yuchen Deng, Toshi-kazu Suzuki
Summary: In this study, normally-off operations were achieved in partially-gate-recessed AlTiO/AlGaN/GaN MIS-FETs by utilizing AlTiO as the gate insulator combined with a partial gate recess method. The experimental results demonstrated favorable performance, including low threshold voltage, small on-resistance, high output current, low sub-threshold swing, and high electron mobility. The combination of interface charge engineering with partial gate recess proved to be effective for GaN-based normally-off device technology.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Heng Zhou, Yuanjie Lv, Yang Liu, Mingyan Wang, Peng Cui, Zhaojun Lin
Summary: This study reports on the DC and frequency characteristics of split-gate heterostructure field-effect transistors (HFETs) with different split-gate lengths. The split-gate HFET exhibits high unilateral power gain and low DC power consumption, making it suitable for various amplifier applications.
MODERN PHYSICS LETTERS B
(2023)
Article
Chemistry, Analytical
Farid Sayar Irani, Ali Hosseinpour Shafaghi, Melih Can Tasdelen, Tugce Delipinar, Ceyda Elcin Kaya, Guney Guven Yapici, Murat Kaya Yapici
Summary: This review provides an in-depth overview of the latest studies on graphene and its strain sensing mechanism, as well as various applications. The article starts by describing the fundamental properties, synthesis techniques, and characterization methods of graphene. It then discusses various types of graphene-based strain sensors and demonstrates the challenges in material synthesis, device fabrication, and integration. Finally, the review describes several applications of graphene-based strain sensors.
Article
Engineering, Electrical & Electronic
Iqbal Preet Singh, Hassan Rahbardar Mojaver, Pouya Valizadeh
Summary: The study investigates the reverse gate-leakage of AlGaN/GaN HFETs at different drain-source voltages, revealing that Fowler-Nordheim tunneling contributes to leakage predominantly at the gate center for lower drain-source voltages, while at higher drain-source voltages, leakage occurs mainly at the drain edge. The electron effective mass is consistently chosen within an acceptable range for analyzing gate-leakage.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Multidisciplinary
Taofei Pu, Shuqiang Liu, Xiaobo Li, Ting-Ting Wang, Jiyao Du, Liuan Li, Liang He, Xinke Liu, Jin-Ping Ao
Summary: AlGaN/GaN heterojunction field-effect transistors (HFETs) with p-GaN cap layer and in-situ grown AlN layer as the gate insulator are developed for normally-off operation. The AlN/p-GaN interface exhibits a more obvious energy band bending and wider depletion region, which positively shifts the threshold voltage. Additionally, the large conduction band offset of AlN/p-GaN helps suppress gate leakage current and enhance gate breakdown voltage. The introduced AlN layer enables a normally-off p-GaN capped AlGaN/GaN HFET with good device performance, including a threshold voltage of 4 V and a gate swing of 13 V, as well as a field-effect mobility of approximately 1500 cm(2) V-1.s(-1) in the 2DEG channel.
Article
Chemistry, Analytical
Balaadithya Uppalapati, Durga Gajula, Manav Bava, Lavanya Muthusamy, Goutam Koley, Antonio Lazaro, Francesca Rolle, Pier Giorgio Spazzini, Aline Piccato
Summary: This paper investigates a simple two-terminal sensor configuration of an AlGaN/GaN triangular microcantilever with a heated apex for airflow detection. The sensor response shows a linear relationship with the airflow rate over a wide range. The sensor exhibits excellent resolution and low power consumption, making it suitable for various sensing applications.
Article
Chemistry, Multidisciplinary
Chaoyang Ti, Atakan B. Ari, M. Cagatay Karakan, Cenk Yanik, Ismet I. Kaya, M. Selim Hanay, Oleksiy Svitelskiy, Miguel Gonzalez, Huseyin Seren, Kamil L. Ekinci
Summary: Piezoresistive strain gauges provide precise electronic readout of mechanical deformations and are now being scaled down for nanotechnology applications. We conducted experiments to study the physical attributes of nanoresistors at different frequencies, finding that the gauge factor increased monotonically with frequency, possibly due to unexpected physics phenomena.
Article
Physics, Multidisciplinary
Mehrnegar Aghayan, Pouya Valizadeh
Summary: This study investigates the reverse gate-leakage current of AlGaN/GaN heterojunction field-effect transistors (HFETs) realized on array of submicron sized fins and conventional mesa isolation feature geometries at room temperature and zero drain-source bias. The significance of leakage from the top surface gate as well as gated etched GaN surfaces, especially sidewalls, is studied for a wide range of gate-source voltages (V-GS). It is found that leakage through the gated GaN surfaces, particularly the sidewalls, is more significant than the leakage from the top surface gate in the explored fin-type HFETs, while the sidewall leakage is of importance only at less negative values of V-GS in the mesa category. The dominance of leakage paths at different V-GS values is attributed to the stronger electric field across the barrier in the gated region of the mesa-type HFET.
Article
Engineering, Electrical & Electronic
Akhil Ranjan, Ravikiran Lingaparthi, Nethaji Dharmarasu, K. Radhakrishnan
Summary: This study establishes a theoretical relationship between the properties of a two-dimensional electron gas (2DEG) in AlGaN/GaN HEMT heterostructure and various gas-sensing characteristics. It is proposed that using a thinner barrier layer in the heterostructure can lead to lower detection limits, higher sensing response, and faster response time. Experimental results confirm these analytical findings by comparing a thin-barrier gas sensor with a thick-barrier gas sensor.
IEEE SENSORS JOURNAL
(2022)
Article
Materials Science, Multidisciplinary
Yongkuan Li, Hongsen Lin, Jianrong Lin, Cheng Zhou, Aixin Luo, Jiachen Yang, Jieyu Zhang, Zhixiang Hong, Xueyan Hou, Peng Xiao, Bingfeng Fan
Summary: Linear piezoelectric materials, specifically undoped ZnO and vanadium-doped ZnO (V-ZnO), were compared for pressure sensing applications. The study showed that the linear piezoelectric ZnO sensor exhibited one-to-one linear correlation between applied pressure and voltage signals, indicating its advantage over the 'sail-like' voltage signals of the ferroelectric V-ZnO sensor. Additionally, the linear piezoelectric ZnO sensor demonstrated superior thermal stability up to 450 degrees C, while the ferroelectric V-ZnO sensor's sensing properties degraded at 150 degrees C.
MATERIALS & DESIGN
(2023)
Article
Engineering, Multidisciplinary
Krzysztof Kwoka, Tomasz Piasecki, Karolina Orlowska, Paulina Grabarczyk, Andrzej Sierakowski, Teodor Gotszalk, Ewelina Gacka, Adrianna Piejko, Krzysztof Gajewski
Summary: The electrical response of vibrating, electrostatically driven microelectromechanical and nanoelectromechanical system (MEMS and NEMS) devices was measured using impedance spectroscopy. A physical model was developed to predict the electrical response based on the structure's dimensions, mechanical properties, and measurement conditions, and it was validated with the results of an electrical equivalent circuit model. The physical model accurately described the inverse fourth power dependence of the electrical response on the distance between electrodes, which was experimentally confirmed using a vibrating electrostatically driven MEMS in vacuum. This validated physical model is useful for optimizing MEMS structures for electrical vibration detection.
Article
Mechanics
Ulises Torres-Herrera, Eugenia Corvera Poire
Summary: By analytically deriving equations of motion, we have identified the dynamic characteristics of fluids confined within elastic nanotubes subjected to periodic bending deflections, and conclusions for two limiting situations. These results open up possibilities for controlling flow at the nanoscale through tube vibrations.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Ning Yu, Zhaohui Ray Li, Alexander McClelland, Francisco Jose del Campo Melchor, Sun Youb Lee, Jae Hwa Lee, Chang-Jin C. J. Kim
Summary: This paper investigates the sustainability of plastrons on superhydrophobic surfaces and their impact on hydrodynamic friction drag reduction in high-speed flows. The study combines existing theories and revises the shear-driven drainage model to account for air diffusion on the superhydrophobic surfaces. Experimental results are in agreement with theoretical estimations, supporting the design of superhydrophobic surfaces for field applications.
JOURNAL OF FLUID MECHANICS
(2023)
