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Nirantar S, Patil B, Tripathi DC, Sethu N, Narayanan RV, Tian J, Bhaskaran M, Walia S, Sriram S. Metal-Air Field Emission Devices - Nano Electrode Geometries Comparison of Performance and Stability. Small 2022; 18:e2203234. [PMID: 36094789 DOI: 10.1002/smll.202203234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Air-channel devices have a special advantage due to the promise of vacuum-like ballistic transport in air, radiation insensitivity, and nanoscale size. Here, achieving high current at low voltage along with considerable mechanical stability is a primary issue. The comparative analysis of four planar and metallic electrode-pair geometries at 10 nm channel length is presented. The impact of nano-electrode-pair geometries on overall device performance is investigated. Air-channel devices are operated at the ultra-low voltage of 5 mV to demonstrate the device dynamics of air-channel devices at low power. Investigations focus on the direct tunneling (DT) mechanism which is dominant in the low-voltage regime. Comparative analysis of different electrode-pair geometries reveals two orders of magnitude increment in the current just by modulating the electrode-pair structure. Theoretical analysis suggests that the emission current is directly related to the active junction area within the metal-air-metal interface at the direct tunneling regime. The geometry-dependent mechanical stability of different electrode pairs is compared by imaging biasing triggered nanoscale structural changes and pulsed biasing stress analysis. The results and claims are confirmed and consolidated with the statistical analysis. Experimental investigations provide strong directions for high-performance and stable devices. In-depth theoretical discussions will enable the accurate modeling of emerging low-power, high-speed, radiation-hardened nanoscale vacuum electronics.
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Affiliation(s)
- Shruti Nirantar
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Basanagounda Patil
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Durgesh C Tripathi
- Faculty of Electrical Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Nilamani Sethu
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Ramakrishnan V Narayanan
- Department of Micro and Nanoelectronics, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Jie Tian
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Sumeet Walia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
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Nirantar S, Mayes E, Sriram S. In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VO x. J Vis Exp 2020. [PMID: 32478740 DOI: 10.3791/61026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Resistive switching crossbar architecture is highly desired in the field of digital memories due to low cost and high-density benefits. Different materials show variability in resistive switching properties due to the intrinsic nature of the material used, leading to discrepancies in the field because of underlying operation mechanisms. This highlights a need for a reliable technique to understand mechanisms using nanostructural observations. This protocol explains a detailed process and methodology of in situ nanostructural analysis as a result of electrical biasing using transmission electron microscopy (TEM). It provides visual and reliable evidence of underlying nanostructural changes in real time memory operations. Also included is the methodology of fabrication and electrical characterizations for asymmetric crossbar structures incorporating amorphous vanadium oxide. The protocol explained here for vanadium oxide films can be easily extended to any other materials in a metal-dielectric-metal sandwiched structure. Resistive switching crossbars are predicted to serve the programmable logic and neuromorphic circuits for next-generation memory devices, given the understanding of the operation mechanisms. This protocol reveals the switching mechanism in a reliable, timely, and cost-effective way in any type of resistive switching materials, and thereby predicts the device's applicability.
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Affiliation(s)
- Shruti Nirantar
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University;
| | - Edwin Mayes
- RMIT Microscopy and Microanalysis Facility, RMIT University
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University;
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Nirantar S, Ahmed T, Ren G, Gutruf P, Xu C, Bhaskaran M, Walia S, Sriram S. Metal-Air Transistors: Semiconductor-Free Field-Emission Air-Channel Nanoelectronics. Nano Lett 2018; 18:7478-7484. [PMID: 30441900 DOI: 10.1021/acs.nanolett.8b02849] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Scattering-free transport in vacuum tubes has always been superior to solid-state transistors. It is the advanced fabrication with mass production capability at low cost which drove solid-state nanoelectronics. Here, we combine the best of vacuum tubes with advanced nanofabrication technology. We present nanoscale, metal-based, field emission air channel transistors. Comparative analysis of tungsten-, gold-, and platinum-based devices is presented. Devices are fabricated with electron beam lithography, achieving channel lengths less than 35 nm. With this small channel length, vacuum-like carrier transport is possible in air under room temperature and pressure. Source and drain electrodes have planar, symmetric, and sharp geometry. Because of this, devices operate in bidirection with voltages <2 V and current values in few tens of nanoamperes range. The experimental data shows that influential operation mechanism is Fowler-Nordheim tunnelling in tungsten and gold devices, while Schottky emission in platinum device. The presented work enables a technology where metal-based switchable nanoelectronics can be created on any dielectric surface with low energy requirements.
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Affiliation(s)
- Shruti Nirantar
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Taimur Ahmed
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Guanghui Ren
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Philipp Gutruf
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Chenglong Xu
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Sumeet Walia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility , RMIT University , Melbourne , VIC 3000 , Australia
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Lee WSL, Kaltenecker K, Nirantar S, Withayachumnankul W, Walther M, Bhaskaran M, Fischer BM, Sriram S, Fumeaux C. Terahertz near-field imaging of dielectric resonators. Opt Express 2017; 25:3756-3764. [PMID: 28241587 DOI: 10.1364/oe.25.003756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
As an alternative to metallic resonators, dielectric resonators can increase radiation efficiencies of metasurfaces at terahertz frequencies. Such subwavelength resonators made from low-loss dielectric materials operate on the basis of oscillating displacement currents. For full control of electromagnetic waves, it is essential that dielectric resonators operate around their resonant modes. Thus, understanding the nature of these resonances is crucial towards design implementation. To this end, an array of silicon resonators on a quartz substrate is designed to operate in transmission at terahertz frequencies. The resonator dimensions are tailored to observe their low-order modes of resonance at 0.58 THz and 0.61 THz respectively. We employ a terahertz near-field imaging technique to measure the complex near-fields of this dielectric resonator array. This unique method allows direct experimental observation of the first two fundamental resonances.
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Headland D, Nirantar S, Withayachumnankul W, Gutruf P, Abbott D, Bhaskaran M, Fumeaux C, Sriram S. Terahertz Magnetic Mirror Realized with Dielectric Resonator Antennas. Adv Mater 2015; 27:7137-7144. [PMID: 26450363 DOI: 10.1002/adma.201503069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/20/2015] [Indexed: 06/05/2023]
Abstract
Single-crystal silicon is bonded to a metal-coated substrate and etched in order to form an array of microcylinder passive terahertz dielectric resonator antennas (DRAs). The DRAs exhibit a magnetic response, and hence the array behaves as an efficient artificial magnetic conductor (AMC), with potential for terahertz antenna and sensing applications.
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Affiliation(s)
- Daniel Headland
- School of Electrical & Electronic Engineering, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Shruti Nirantar
- Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, 3000, Australia
- Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Withawat Withayachumnankul
- School of Electrical & Electronic Engineering, The University of Adelaide, Adelaide, South Australia, 5005, Australia
- Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, 3000, Australia
- Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, 152-8552, Meguro-ku, Tokyo, Japan
| | - Philipp Gutruf
- Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, 3000, Australia
- Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Derek Abbott
- School of Electrical & Electronic Engineering, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, 3000, Australia
- Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Christophe Fumeaux
- School of Electrical & Electronic Engineering, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, 3000, Australia
- Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3000, Australia
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