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Thermal Annealing and Radiation Effects on Structural and electrical Properties of NbN/GaN Superconductor/Semiconductor Junction

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arXiv 2025年

作者： Margiotta, Stephen Liu, Binzhi Khan, Saleh Ahmed Ortiz, Gabriel Calderon Ibreljic, Ahmed Hwang, Jinwoo Bhuiyan, A.F.M. Anhar Uddin Department of Electrical and Computer Engineering University of Massachusetts Lowell LowellMA01854 United States Lincoln Laboratory Massachusetts Institute of Technology LexingtonMA02421 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

In the rapidly evolving field of quantum computing, niobium nitride (NbN) superconductors have emerged as integral components due to their unique structural properties, including a high superconducting transition temperature, exceptional electrical conductivity, and compatibility with advanced device architectures. This study investigates the impact of high temperature annealing and high dose gamma irradiation on the structural, electrical and superconducting properties of NbN films grown on GaN via reactive DC magnetron sputtering. The as-deposited cubic δ-NbN (111) films exhibited high intensity distinct x-ray diffraction (XRD) peak, a high superconducting transition temperature (Tc) of 12.82 K, and an atomically flat surface. Annealing at 500 °C and 950 °C for varying durations revealed notable structural and surface changes. High resolution scanning transmission electron microscopy (STEM) indicated improved local ordering, while atomic force microscopy (AFM) showed reduced surface roughness after annealing. X-ray photoelectron spectroscopy (XPS) revealed a gradual increase in the Nb/N ratio with higher annealing temperatures and durations. High-resolution XRD and STEM analysis showed lattice constant modifications in δ-NbN films, attributed to residual stress changes following annealing. Additionally, XRD φ-scans revealed sixfold symmetry in NbN films due to rotational domains relative to GaN. While Tc remained stable after annealing at 500 °C, increasing the annealing temperature to 950 °C degraded Tc to ~8 K and reduced the residual resistivity ratio (RRR) from 0.85 in as-deposited films to 0.29 after 30 minutes. The effects of high-dose gamma radiation (5 Mrad (Si)) were also studied, demonstrating minimal changes to crystallinity and superconducting performance, indicating excellent radiation resilience. These findings highlight the potential of NbN superconductors for integration into advanced quantum devices and its suitability for applications in radiatio

关键词： Gallium nitride

Frequency Multiplexed Emission from Cavity-Enhanced T Centers

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Frequency Multiplexed Emission from Cavity-Enhanced T Center...

Conference on Lasers and Electro-Optics (CLEO)

作者： Lukasz Komza Xueyue Zhang Yu-Lung Tang Hanbin Song Alp Sipahigil Department of Physics University of California Berkeley Berkeley California USA Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California USA Department of Electrical Engineering and Computer Sciences University of California Berkeley Berkeley California USA Department of Materials Science and Engineering University of California Berkeley Berkeley California USA

To enable efficient spin-photon interfaces with T centers, cavity-enhanced emission is essential. We build an integrated photonics platform demonstrating cavity-enhanced emission from multiple T centers across distinc... 详细信息

ISBN: (纸本)9798350369311

关键词： Frequency division multiplexing Electro-optical waveguides Photonics

One-Dimensional van der Waals Quantum materials - State of the Art and Perspectives

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arXiv 2022年

作者： Balandin, Alexander A. Kargar, Fariborz Salguero, Tina T. Lake, Roger K. Department of Electrical and Computer Engineering Materials Science and Engineering Program University of California RiversideCA92521 United States Department of Chemistry University of Georgia AthensGA30602 United States

The advent of graphene and other two-dimensional van der Waals materials, with their unique electrical, optical, and thermal properties, has resulted in tremendous progress for fundamental science. Recent developments suggest that taking one more step down in dimensionality - from monolayer, atomic sheets to individual atomic chains - can bring exciting prospects as the ultimate limit in material downscaling is reached while establishing an entirely new field of one-dimensional quantum materials. Here we review this emerging area of one-dimensional van der Waals quantum materials and anticipate its future directions. We focus on quantum effects associated with the charge-density-wave condensate, strongly-correlated phenomena, topological phases, and other unique physical characteristics, which are attainable specifically in van der Waals materials of lower dimensionality. Possibilities for engineering the properties of quasi-one-dimensional materials via compositional changes, vacancies, and defects, as well as the prospects of their applications in composites are also discussed. Copyright © 2022, The Authors. All rights reserved.

关键词： Van der Waals forces

Comprehensive Time Dependent Dielectric Breakdown (TDDB) Characterization of Ferroelectric Capacitors Under Bipolar Stress Conditions

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Comprehensive Time Dependent Dielectric Breakdown (TDDB) Cha...

Annual International Symposium on Reliability Physics

作者： Priyankka Gundlapudi Ravikumar Prasanna Venkatesan Ravindran Khandker Akif Aabrar Taeyoung Song Sharadindu Gopal Kirtania Dipjyoti Das Chinsung Park Nashrah Afroze Mengkun Tian Shimeng Yu Ahmad Ehtesham Islam Suman Datta Souvik Mahapatra Asif Khan School of Electrical and Computer Engineering Georgia Institute of Technology GA USA Institute of Materials GA USA Sensors directorate Air Force Research Laboratory (AFRL) OH USA School of Material Science and Engineering Georgia Institute of Technology GA USA Department of Electrical Engineering Indian Institute of Technology Mumbai India

ISBN: (数字)9798350369762

ISBN: (纸本)9798350369779

In this work, we report the first comprehensive time-dependent dielectric breakdown (TDDB) study on ultra-thin HfO 2 -based ferroelectric under bipolar stress conditions. Here, field cycling is done on 7 nm Hf 0.5 Zr 0.5 O 2 (HZO) capacitors at different temperatures and bipolar stress fields. Despite involving polarization switching and associated large internal electric fields, bipolar cycling of ferroelectric HZO is shown to exhibit similar time-dependent dielectric breakdown acceleration trends to that of traditional dielectrics like SiO 2 . Notably, the temperature acceleration of time-dependent dielectric breakdown shows a linear dependence on the stress field similar to SiO 2 . Further, the field acceleration of time-dependent dielectric breakdown in ferroelectric HZO, while exhibiting functionally similar temperature dependence to that of SiO 2 , demonstrates considerably greater sensitivity to temperature.

关键词： Silicon compounds Temperature sensors Temperature dependence Polarization Temperature Capacitors Switches

EARLY DETECTION OF SIMULATED HERBIVORE ATTACKS IN SORGHUM FIELDS THROUGH THE DEPLOYMENT OF VERY-LOW-POWER GAS SENSOR NETWORK

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EARLY DETECTION OF SIMULATED HERBIVORE ATTACKS IN SORGHUM FI...

2022 Solid-State Sensors, Actuators and Microsystems Workshop, Hilton Head 2022

作者： Khan, Shakir-Ul Haque Tope, Sayali Karkhanis, Mohit Hataska, Bryan Noh, Seungbeom Dalapati, Rana Bulbul, Ashrafuzzaman Mural, Ravi V. Banerjee, Aishwaryadev Kim, Kyeongheon Schnable, James C. Ji, Mingyue Mastrangelo, Carlos Zang, Ling Kim, Hanseup Electrical and Computer Engineering University of Utah Salt Lake CityUT8411 United States Materials Science and Engineering University of Utah Salt Lake CityUT84112 United States Department of Agronomy and Horticulture University of Nebraska LincolnNE685 United States Department of Convergence Electronic Engineering Gyeongsang National University 52828 Korea Republic of

ISBN: (纸本)9781940470047

This paper reports a novel method of detecting simulated herbivore attacks (mechanical damages) on a plant by sensing emitted gas, which was enabled by developing and deploying a very-low-power gas sensor network in an actual sorghum farm. When a group of nearby sorghum leaves were cut (simulating herbivore attacks), the damaged plants started emitting a unique volatile organic compound (VOC) marker, hexanal, ultimately increasing its concentration up to 60 ppm in 62 minutes within an area of less than 1.0 m diameter from the cut point. The emitted hexanal was detected by a near-zero-power ( © 2022 TRF.

关键词： Damage detection

Heterostructure and Interfacial engineering for Low-Resistance Contacts to Ultra-Wide Bandgap AlGaN

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arXiv 2024年

作者： Zhu, Yinxuan Allerman, Andrew A. Joishi, Chandan Pratt, Jonathan Merwin Xavier, Agnes Maneesha Dominic Ortiz, Gabriel Calderon Klein, Brianna A. Armstrong, Andrew Hwang, Jinwoo Rajan, Siddharth Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States Sandia National Laboratories AlbuquerqueNM87123 United States

We report on the heterostructure and interfacial engineering of metalorganic chemical vapor deposition (MOCVD) grown reverse-graded contacts to ultra-wide bandgap AlGaN. A record low contact resistivity of 1.4 x 10-6 Ω.cm2 was reported on an Al0.82Ga0.18N metal semiconductor field effect transistor (MESFET) by compositionally grading the contact layer from Al0.85Ga0.15N → Al0.14Ga0.86N with degenerate doping and proper interfacial engineering considering bandgap-narrowing-induced band offset between channel and contact layer. This represents orders-of-magnitude of lower contact resistivity than that obtained in similar MOCVD-grown structures. A detailed, layer-by-layer analysis of the reverse graded contact and TCAD simulation of the bandgap narrowing effect highlighted that the reverse graded contact layer itself is extremely conductive and interfacial resistance due to bandgap-narrowing-induced barrier between contact and channel dominates the contact resistance. Copyright © 2024, The Authors. All rights reserved.

关键词： Aluminum gallium nitride

Dispersion Control of High-quality Ge23Sb7S70 Reflowed Wedge Resonators

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Dispersion Control of High-quality Ge23Sb7S70 Reflowed Wedge...

Conference on Lasers and Electro-Optics (CLEO)

作者： Bo Xu Michael Grayson Thariq Shanavas Juliet T. Gopinath Wounjhang Park Department of Physics University of Colorado Boulder Colorado USA Department of Electrical Computer and Energy Engineering University of Colorado Boulder Colorado USA Materials Science and Energy Engineering University of Colorado Boulder CO USA

We report Ge 23 Sb 7 S 70 chalcogenide reflowed wedge resonators with up to 10 6 quality factors fabricated through reflow. The continuously varying sidewall angle can be engineered to support flat, close-to-zero di... 详细信息

ISBN: (纸本)9781957171258

关键词： Dispersion Frequency combs Near infrared radiation Optical constants Scanning electron microscopy Whispering gallery modes

Giant spin Hall effect with multi-directional spin components in Ni4W

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arXiv 2024年

作者： Yang, Yifei Lee, Seungjun Chen, Yu-Chia Jia, Qi Sousa, Duarte Odlyzko, Michael Garcia-Barriocanal, Javier Yu, Guichuan Haugstad, Greg Fan, Yihong Huang, Yu-Han Lyu, Deyuan Cresswell, Zach Low, Tony Wang, Jian-Ping Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States Characterization Facility University of Minnesota MinneapolisMN55455 United States Department of Chemical Engineering and Materials Science University of Minnesota MinneapolisMN55455 United States

Spin-orbit torque (SOT) can be used to efficiently manipulate the magnetic state of magnetic materials, which is an essential element for memory and logic applications. Due to symmetry constraints, only in-plane spins can be injected into the ferromagnet from the underlying SOT layer for conventional SOT materials such as heavy metals and topological materials. Through the use of materials with low symmetries, or other symmetry breaking approaches, unconventional spin currents with out-of-plane polarization has been demonstrated and enabled field-free deterministic switching of perpendicular magnetization. Despite this progress, the SOT efficiency of these materials has typically remained low. Here, we report a giant SOT efficiency of 0.85 in sputtered Ni4W/CoFeB heterostructure at room temperature, as evaluated by second harmonic Hall measurements. In addition, due to the low crystal symmetry of Ni4W, unconventional out-of-plane and Dresselhaus-like spin components were observed. Macro-spin simulation suggests our spin Hall tensor to provide about an order of magnitude improvement in the magnetization switching efficiency, thus broadening the path towards energy efficient spintronic devices using low-symmetry materials. Copyright © 2024, The Authors. All rights reserved.

关键词： Spin Hall effect

Performance comparison of InGaN-based 40–80 μm micro-LEDs fabricated with and without plasma etching

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materials Today Advances 2024年 22卷

作者： Lo, Yu-Yun Chen, Yi-Ho Hsu, Yun-Cheng Lee, Tzu-Yi Hung, Yu-Ying Kao, Yu-Cheng Zan, Hsiao-Wen Wuu, Dong- Sing Kuo, Hao-Chung Samukawa, Seiji Horng, Ray-Hua Institute of Electronics National Yang Ming Chiao Tung University 1001 University Road Hsinchu30010 Taiwan Department of Photonics College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Graduate Degree Program of College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Department of Materials Science and Engineering National Chung Hsing University Taichung40227 Taiwan Department of Applied Materials and Optoelectronic Engineering National Chi Nan University Nantou54561 Taiwan Semiconductor Research Center Hon Hai Research Institute Taipei11492 Taiwan Institute of Communications Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan

The fabrication of InGaN-based blue 4✕4 array micro-LEDs (μLEDs) with 40 μm ✕40 μm chip size and 2✕2 array μLEDs with 80 μm ✕80 μm chip size etching by the inductive coupled plasma reactive ion etching (ICPRIE) and defect-free neutral beam etching (NBE) processes was studied in this work. In μLEDs of this size, the influence of defects formation in the sidewalls on EQE was evaluated. There was almost no difference in EQE between μLEDs array etched by the NBE process no matter 40 μm ✕40 μm and 80 μm ✕80 μm, but the dependence was observed in the ICPRIE. Even with this size, it was found that the size effect of EQE is smaller than that in case of using ICPRIE for defect-free neutral beam etching. This impact is substantial since μLED predominantly operated at low current density, around 1–5 A/cm2. Consequently, the reduction of defect density, encompassing both internal and sidewall defects, becomes imperative even in 40–80 μm InGaN-based μLEDs. This not only improves the overall efficiency of μLEDs but also fortifies the brightness stability of μLED displays if process etching by NBE. It was also found that the etching shape had an influence on EQE. It could be attributed to fact that the etching profile angle of NBE was more vertical than that of ICPRIE. Because the different angles of the mesa resulted in different light intensity. The μLEDs emitting with a wavelength of 450 nm, the light extraction efficiency and intensity at a mesa angle 58° of NBE etching μLEDs was about 8% lower than those of an angle (38°) of ICPRIE etching μLEDs by simulation. © The Authors

关键词： Light emitting diodes