Article
Physics, Applied
Ping Wang, Ding Wang, Nguyen M. Vu, Tony Chiang, John T. Heron, Zetian Mi
Summary: Ferroelectricity has been successfully demonstrated in ScxAl1-xN epitaxial films grown on GaN templates by molecular beam epitaxy, showing distinct polarization switching and excellent properties, such as a high coercive field and long polarization retention time. This achievement opens up possibilities for integrating high-performance ferroelectric functionality into established semiconductor platforms for various electronic and photonic device applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Ping Wang, Ding Wang, Shubham Mondal, Zetian Mi
Summary: In this study, robust ferroelectricity was demonstrated in single-crystalline thin films. The crystallographic alignment was confirmed using x-ray diffraction measurements. The highly uniform coercive field and remnant polarization were observed in the nearly lattice-matched heterostructure. The reliability of the ferroelectricity was systematically characterized and showed negligible degradation after a large number of switching cycles. This research provides a feasible pathway for fully epitaxial integration of ferroelectricity into nitride heterostructures, with important applications in various fields.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Ding Wang, Shubham Mondal, Jiangnan Liu, Mingtao Hu, Ping Wang, Samuel Yang, Danhao Wang, Yixin Xiao, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: We demonstrate ferroelectric switching in yttrium-doped nitride semiconductors. Yttrium 0.07Al0.93N films were grown on GaN/sapphire templates and exhibited a coercive field of 6 MV/cm and a switchable polarization of 130 mu C/cm(2). Ferroelectric switching was confirmed through capacitance-voltage loops and polarity-sensitive wet etching. This study expands the family of nitride ferroelectrics and opens up possibilities for applications in III-nitride based devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Camille Barbier, Ludovic Largeau, Noelle Gogneau, Laurent Travers, Christophe David, Ali Madouri, Dyhia Tamsaout, Jean-Christophe Girard, Guillemin Rodary, Hervei Montigaud, Christophe Durand, Maria Tchernycheva, Frank Glas, Jean-Christophe Harmand
Summary: This study investigates the nucleation of GaN nanostructures on graphene as growth substrates for semiconductors. By using plasma-assisted molecular beam epitaxy, the incubation time before the epitaxy of the first GaN islands is explored. It is found that graphene is modified after nitrogen plasma exposure, and C-N bonds are identified. The adhesion between graphene and GaN nanostructures is found to be strong due to the incorporation of pyridinic N atoms in the lattice. This work demonstrates the modification of a graphene monolayer before nucleation and growth of GaN nanowires becomes possible.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
Rahmat Hadi Saputro, Ryo Matsumura, Naoki Fukata
Summary: This study reveals the mechanism of dopant redistribution in Sb-doped Ge epitaxial films grown by molecular beam epitaxy, providing insights into the behavior of substituted Sb atoms in forming n-type Ge films. The understanding of these processes opens up possibilities for achieving n(+)-Ge thin films for Ge-based devices with improved electrical properties.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Nanoscience & Nanotechnology
Mohammad Fazel Vafadar, Songrui Zhao
Summary: This study reports the use of radio-frequency plasma-assisted molecular beam epitaxy to achieve selective area epitaxy (SAE) of gallium nitride (GaN) nanowires at low substrate temperatures. The researchers successfully controlled the top-surface morphology of the nanowires through low temperature epitaxy. The results of this work will benefit the development of a fully controllable nanophotonic platform for various photonic devices.
ACS APPLIED NANO MATERIALS
(2022)
Article
Physics, Applied
P. John, P. Vennegues, H. Rotella, C. Deparis, C. Lichtensteiger, J. Zuniga-Perez
Summary: Epitaxial growth of Mg3N2 thin films by molecular beam epitaxy has been achieved, with the microstructure displaying column twist but narrow rocking curve peaks do not necessarily indicate high crystalline quality.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Ding Wang, Ping Wang, Minming He, Jiangnan Liu, Shubham Mondal, Mingtao Hu, Danhao Wang, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: In this Letter, fully epitaxial ScAlN/AlGaN/GaN based ferroelectric high electron mobility transistors (HEMTs) were demonstrated using molecular beam epitaxy. The fabricated ferroelectric gate HEMTs showed counterclockwise hysteretic transfer curves with a wide threshold voltage tuning range, a large ON/OFF ratio, and reconfigurable output characteristics. The high quality ferroelectric gate stack and effective ferroelectric polarization coupling lead to improved subthreshold performance. These results provide fundamental insight into the ferroelectric polarization coupling and threshold tuning processes in ferroelectric nitride heterostructures and have promising applications in next-generation electronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Dong Han, Wen-Qi Wei, Ming Ming, Zihao Wang, Ting Wang, Jian-Jun Zhang
Summary: In recent years, there has been a strong demand for GaSb-on-Si direct heteroepitaxy to expand the operating wavelength range to mid-infrared and high-mobility applications. However, the growth of high-quality GaSb films on Si is challenging due to the generation of high-density defects. In this study, we proposed a novel design and growth strategy to achieve the annihilation of antiphase boundaries (APBs) and the reduction of threading dislocation density (TDD) through the use of a V-grooved Si hollow structure and InGaSb/GaSb dislocation filtering layers. The reported results greatly improve the overall quality of epitaxial Si-based antimonide, benefiting various devices and critical applications.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Nikitas Siannas, Christina Zacharaki, Polychronis Tsipas, Dong Jik Kim, Wassim Hamouda, Cosmin Istrate, Lucian Pintilie, Martin Schmidbauer, Catherine Dubourdieu, Athanasios Dimoulas
Summary: Synapses play a vital role in information processing, learning, and memory formation in the brain. Electronic synaptic devices that emulate the behavior of biological synapses have the potential to enable high-performance, energy-efficient, and scalable neuromorphic computing. A new ferroelectric device on silicon, a field-effect memristor, has been reported, which can access multiple states through the field-effect modulation in the semiconductor and dynamically adjust synaptic strength to mimic memory plasticity.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Iwan Susanto, Chi-Yu Tsai, Yen-Teng Ho, Ping-Yu Tsai, Ing-Song Yu
Summary: Van der Waals epitaxial GaN thin films were successfully grown on c-sapphire substrates with a sp(2)-bonded two-dimensional MoS2 buffer layer. Higher substrate temperatures during molecular beam epitaxy (MBE) growth led to improved crystallinity and optical properties of the GaN films, as well as smoother surface morphology and stable chemical composition. Exfoliation of the GaN/MoS2 heterostructure was also examined, revealing the largest granular structures with good crystallinity in films grown at 700 degrees C.
Article
Chemistry, Multidisciplinary
Jisoo Moon, Qiang Zou, Huimin Zhang, Olaf M. J. van 't Erve, Nicholas G. G. Combs, Lian Li, Connie H. H. Li
Summary: Magnetic field-induced spin nematicity is observed in tetragonal FeTe, the parent compound of iron chalcogenide superconductors. In situ atomic resolution scanning tunneling microscopy imaging confirms the bicollinear antiferromagnetic order in the compound. A 2-fold anisotropy is observed in in-plane angle-dependent magnetoresistance measurements, indicating the presence of magnetic field-induced nematicity. This 2-fold anisotropy persists up to 300 K, well above the bicollinear antiferromagnetic ordering temperature of 75 K, suggesting the existence of a magnetic field-induced spin nematic phase in the antiferromagnet FeTe.
Article
Chemistry, Multidisciplinary
Karol Olszewski, Marta Sobanska, Vladimir G. Dubrovskii, Egor D. Leshchenko, Aleksandra Wierzbicka, Zbigniew R. Zytkiewicz
Summary: This study focused on the growth of GaN nanowires on Si(111) substrates using plasma-assisted molecular beam epitaxy, specifically investigating the orientation and growth rate of the nanowires. The researchers found that vertically aligned nanowires grew faster and produced more regular ensembles compared to inclined nanowires. These densely packed ensembles of vertically aligned GaN nanowires on ZrN/Si(111) surfaces are highly relevant for device applications.
Article
Chemistry, Physical
Danhao Wang, Ding Wang, Peng Zhou, Mingtao Hu, Jiangnan Liu, Shubham Mondal, Tao Ma, Ping Wang, Zetian Mi
Summary: Through high-resolution X-ray photoelectron spectroscopy measurements, we discovered a thick oxide layer on ScAlN when exposed to air, which significantly affects its characterization and electronic structure evaluation. By excluding the possible impact from the surface oxide layer, the band alignment of Sc0.18Al0.82N/GaN can be accurately determined. Simulation results further demonstrate that the Sc0.18Al0.82N barrier layer offers excellent charge carrier confinement and a high density of two-dimensional electron gas (2DEG) at the heterostructure interface, crucial for high-performance GaN-based high electron mobility transistors (HEMTs).
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Mansi Agrawal, Anubha Jain, Vishakha Kaushik, Akhilesh Pandey, B. R. Mehta, R. Muralidharan
Summary: In this study, catalyst-free GaN nanowires were grown on Si (111) substrates by plasma-assisted molecular beam epitaxy, followed by the deposition of a few layers of MoS2 by chemical vapor deposition. The morphology and vibrational properties of the MoS2/GaN nanowires on Si (111) substrates were analyzed using scanning electron microscopy and Raman spectroscopy. The results indicate the potential of MoS2/GaN nanowires heterojunction for future optoelectronic devices due to their exceptional structural and vibrational properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Ayush Pandey, Jungwook Min, Maddaka Reddeppa, Yakshita Malhotra, Yixin Xiao, Yuanpeng Wu, Kai Sun, Zetian Mi
Summary: By developing nanowire excitonic LEDs, the challenge of reduced efficiency in quantum well LEDs at small dimensions can be overcome. A submicron scale green-emitting LED with an external quantum efficiency of 25.2% and a wall-plug efficiency of 20.7% was achieved, the highest values reported for LEDs of this size to our knowledge. Critical factors for achieving excitonic micro-LEDs were identified, including epitaxy of nanostructures for strain relaxation, utilization of semipolar planes to minimize polarization effects, and formation of nanoscale quantum confinement to enhance electron-hole wave function overlap. This work provides a viable path to break the efficiency bottleneck of nanoscale optoelectronics.
Article
Multidisciplinary Sciences
Peng Zhou, Ishtiaque Ahmed Navid, Yongjin Ma, Yixin Xiao, Ping Wang, Zhengwei Ye, Baowen Zhou, Kai Sun, Zetian Mi
Summary: Production of hydrogen fuel from sunlight and water is a promising pathway for carbon neutrality. A strategy using pure water, concentrated solar light, and an indium gallium nitride photocatalyst has achieved a solar-to-hydrogen efficiency of 9.2%. The strategy promotes forward hydrogen-oxygen evolution and inhibits reverse hydrogen-oxygen recombination by operating at an optimal reaction temperature, which can be achieved by harvesting infrared light in sunlight.
Article
Chemistry, Physical
Yuji Zhao, Mingfei Xu, Xuanqi Huang, Justin Lebeau, Tao Li, Dawei Wang, Houqiang Fu, Kai Fu, Xinqiang Wang, Jingyu Lin, Hongxing Jiang
Summary: III-nitride InGaN material is an ideal candidate for high-performance photovoltaic solar cells, especially in high-temperature applications. This paper provides a comprehensive review of recent developments in InGaN-based solar cells, including theoretical modeling, material epitaxy, device engineering, and high-temperature measurement. Substrate technology and unique properties of InGaN materials, such as polarization control and positive thermal coefficient, are highlighted. Outstanding high-temperature InGaN-based solar cells with quantum efficiency approaching 80% at 450 degrees C have been demonstrated. Future innovations in epitaxy science, device engineering, and integration methods are required to further enhance the efficiency and expand the applications of InGaN-based solar cells.
MATERIALS TODAY ENERGY
(2023)
Editorial Material
Materials Science, Multidisciplinary
Grace Xing, Zetian Mi, Srabanti Chowdhury
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Jiarui Gong, Jie Zhou, Ping Wang, Tae-Hyeon Kim, Kuangye Lu, Seunghwan Min, Ranveer Singh, Moheb Sheikhi, Haris Naeem Abbasi, Daniel Vincent, Ding Wang, Neil Campbell, Timothy Grotjohn, Mark Rzchowski, Jeehwan Kim, Edward T. Yu, Zetian Mi, Zhenqiang Ma
Summary: This study successfully demonstrates the creation, transfer-printing, and characteristics of high-quality single-crystalline aluminum nitride nanomembranes (AlN NMs). The crystalline quality of the NMs remains intact after transfer, and partial relaxation of tensile stress is observed. Additionally, piezoelectricity at the nanoscale is confirmed. This research provides a novel approach for the development of AlN-based heterogeneous integration and future nanoelectronics and optoelectronics.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
David Arto Laleyan, Woncheol Lee, Ying Zhao, Yuanpeng Wu, Ping Wang, Jun Song, Emmanouil Kioupakis, Zetian Mi
Summary: Two-dimensional hexagonal boron nitride (h-BN) shows great promise for far ultraviolet (UV-C) light emission with higher quantum efficiency than other indirect bandgap materials, enabled by strong excitonic effects and efficient exciton-phonon interactions. This study offers a new approach for the design and development of far UV-C optoelectronic devices and quantum photonic devices using 2D semiconductor active regions.
Article
Physics, Applied
Fengyan Yang, Guangcanlan Yang, Ding Wang, Ping Wang, Juanjuan Lu, Zetian Mi, Hong X. Tang
Summary: In this study, high-fidelity ferroelectric domain switching and periodic poling of Al-polar ScAlN thin film was demonstrated, which was epitaxially grown on a c-axis sapphire substrate using gallium nitride as a buffer layer. This advancement in controlling the polarization of epitaxial ScAlN presents great potential for its application in ferroelectric storage and nonlinear optics.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Ding Wang, Shubham Mondal, Jiangnan Liu, Mingtao Hu, Ping Wang, Samuel Yang, Danhao Wang, Yixin Xiao, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: We demonstrate ferroelectric switching in yttrium-doped nitride semiconductors. Yttrium 0.07Al0.93N films were grown on GaN/sapphire templates and exhibited a coercive field of 6 MV/cm and a switchable polarization of 130 mu C/cm(2). Ferroelectric switching was confirmed through capacitance-voltage loops and polarity-sensitive wet etching. This study expands the family of nitride ferroelectrics and opens up possibilities for applications in III-nitride based devices.
APPLIED PHYSICS LETTERS
(2023)
Review
Optics
Xiaoyu Yang, Li Ma, Maotao Yu, Hao-Hsin Chen, Yongqiang Ji, An Hu, Qixuan Zhong, Xiaohan Jia, Yanju Wang, Yuzhuo Zhang, Rui Zhu, Xinqiang Wang, Changjun Lu
Summary: This paper focuses on the lagging progress of blue perovskite light-emitting diodes (PeLEDs) compared to their red and green counterparts. Recent advances and noteworthy strategies in optimizing microstructures, energy landscapes, and charge behaviors of wide-bandgap perovskite emitters are systematically reviewed. The stability of blue perovskite emitters and related devices is also discussed. In the end, a technical roadmap for fabricating state-of-the-art blue PeLEDs is proposed.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Valentin Jmerik, Vladimir Kozlovsky, Xinqiang Wang
Summary: This review focuses on UVC emitters with electron-beam pumping of heterostructures with quantum wells in an (Al,Ga)N material system. The advantages of these emitters include the absence of p-type doping and the ability to achieve high-output optical power values in the UVC range. The review discusses the world experience in implementing various UV emitters and pays special attention to the production of heterostructures with multiple quantum wells/two-dimensional quantum disks of GaN/AlN.
Article
Multidisciplinary Sciences
Fang Liu, Tao Wang, Xin Gao, Huaiyuan Yang, Zhihong Zhang, Yucheng Guo, Ye Yuan, Zhen Huang, Jilin Tang, Bowen Sheng, Zhaoying Chen, Kaihui Liu, Bo Shen, Xin-Zheng Li, Hailin Peng, Xinqiang Wang
Summary: Transferred graphene is a promising platform for fabricating multifunctional devices beyond the limitations of conventional substrates. The preferred epitaxy for single-crystal III-nitrides on wet-transferred graphene is quasi-vdWe, as demonstrated by inhibiting lattice inversion and resulting in a single-crystal film. This work is essential for the development of III-nitride semiconductor devices on two-dimensional materials such as graphene.
Article
Engineering, Electrical & Electronic
Suhyun Nam, Wenhao Peng, Ping Wang, Ding Wang, Zetian Mi, Amir Mortazawi
Summary: Modern wireless communication systems are becoming more complex and pose new challenges for RF front-end design. This study introduces a film bulk acoustic wave resonator (FBAR) with a composite ferroelectric/piezoelectric transduction layer that can operate selectively at higher order resonant modes in the millimeter wave spectrum without compromising k(t)(2). The resonator has a fundamental mode at GHz with k(t)(2) of 5.2%, but can switch to a higher order response at 31 GHz with k(t)(2) of 5.5%).
IEEE MICROWAVE AND WIRELESS TECHNOLOGY LETTERS
(2023)
Article
Physics, Condensed Matter
Teng Fan, Ning Tang, Jiaqi Wei, Shixiong Zhang, Zhenhao Sun, Guoping Li, Jiayang Jiang, Lei Fu, Yunfan Zhang, Ye Yuan, Xin Rong, Weikun Ge, Xinqiang Wang, Bo Shen
Summary: The effects of annealing in an oxygen atmosphere on beta-Ga2O3 epilayers were studied using X-ray photoelectron spectroscopy, photoluminescence, and Fourier-transform infrared spectroscopy. The results showed that as the annealing temperature increased, the proportions of Ga3+ and O-L (lattice oxygen) increased, indicating the reduction of V-O defects. The changes in photoluminescence emissions indicated improved crystal quality and a decrease in V-O(1), V-O(2), and V-Ga defects. The annealing process led to the filling of V-O and V-Ga defects with oxygen and gallium atoms, primarily attributed to the bonding structures of Ga(1)-O(1) and Ga(1)-O(2) in GaO4 tetrahedra. These findings provide detailed information and guidelines for reducing intrinsic point defects in beta-Ga2O3.
MICRO AND NANOSTRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Zhen Huang, Renchun Tao, Duo Li, Zexing Yuan, Shanshan Sheng, Tao Wang, Tai Li, Zhaoying Chen, Ye Yuan, Junjie Kang, Zhiwen Liang, Qi Wang, Pengfei Tian, Bo Shen, Xinqiang Wang
Summary: In order to improve the performance of GaN-based green micro-light emitting diodes (mu-LEDs) array, a modular-architected p-type region is proposed, which consists of polarization-induced graded AlGaN and Al0.2Ga0.8N/GaN superlattices (SLs) to enhance p-type conductivity. The designed p-type structure exhibits a high hole concentration and excellent conductivity. The fabricated mu-LEDs array shows improved resistance, light output power, and data rate in comparison to devices with different p-type layers.
ADVANCED PHOTONICS RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Yong He, Jing Lu, Xinqiang Wang, Jun-jie Shi
Summary: This article proposes a design strategy for achieving superconductivity at ambient pressure by constructing few-hydrogen metal-bonded perovskite hydrides, such as Al4H, to address the challenge of high-pressure sample preparation. It predicts that Al4H has a favorable critical temperature Tc of up to 54 K under ambient pressure.
