Carbon nanotube RF transistors are predicted to offer good performance and high linearity when operated in the ballistic transport and quantum capacitance regime; however, realization of such transistors has been very challenging. In this paper, we introduce a self-aligned fabrication method for carbon nanotube RF transistors, which incorporate a T-shaped (mushroom-shaped) aluminum gate, with oxidized aluminum as the gate dielectric. In this way, the channel length can be scaled down to 140 nm, which enables quasi-ballistic transport, and the gate dielectric is reduced to 2-3 nm aluminum oxide, leading to quasi-quantum capacitance operation. A current-gain cutoff frequency (f(t)) up to 23 GHz and a maximum oscillation frequency (f(max)) of 10 GHz are demonstrated. Furthermore, the linearity properties of nanotube transistors are characterized by using the 1 dB compression point measurement with positive power gain for the first time, to our knowledge. Our work reveals the importance and potential of separated semiconducting nanotubes for various RF applications.
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http://dx.doi.org/10.1021/nn301972j | DOI Listing |
Materials (Basel)
January 2025
School of Microelectronics and Artificial Intelligence, Kaili University, Kaili 556011, China.
From the discovery of carbon nanotubes to the ability to prepare high-purity semiconductor carbon nanotubes in large quantities, the large-scale fabrication of carbon nanotube transistors (CNT) will become possible. In this paper, a carbon nanotube transistor featuring a buried-gate structure, employing an etching process to optimize the surface flatness of the device and enhance its performance, is presented. This CNT thin-film transistor has a current switching ratio of 10, a threshold voltage of around 1 V, and a mobility that can reach 6.
View Article and Find Full Text PDFRecent Pat Nanotechnol
January 2025
Department of Electronic Engineering, University of KwaZulu-Natal, Durban, South Africa.
Background: Thin Film Transistors (TFTs) are increasingly prevalent electrical components in display products, ranging from smartphones to diagonal flat panel TVs. The limitations in existing TFT technologies, such as high-temperature processing, carrier mobility, lower ON/OFF ratio, device mobility, and thermal stability, result in the search for new semiconductor materials with superior properties.
Objective: The main objective of this present work is to fabrícate the efficient Single-Walled Carbon Nanotube Thin Film Transistor (TFT) for flat panel display.
Nano Lett
January 2025
Key Lab for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics, School of Electronics, Peking University, Beijing 100871, China.
One-time programmable (OTP) memory is an essential component in chips, which has extremely high security to protect the stored critical information from being altered. However, traditional OTP memory based on the thermal breakdown of the dielectric has a large programming current, which leads to high power consumption. Here, we report a gate tunneling-induced "cold" breakdown phenomenon in carbon nanotube (CNT) field-effect transistors, and based on this we construct a "cold" fuse (C-fuse) memory where applying a mild gate voltage can break down the CNT channel without damaging the gate dielectric.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Institute of Advanced Materials and Systems, Sookmyung Women's University, Seoul 04310, Republic of Korea.
Multivalued logic (MVL) systems, in which data are processed with more than two logic values, are considered a viable solution for achieving superior processing efficiency with higher data density and less complicated system complexity without further scaling challenges. Such MVL systems have been conceptually realized by using negative transconductance (NTC) devices whose channels consist of van der Waals (vdW) heterojunctions of low-dimensional semiconductors; however, their circuit operations have not been quite ideal for driving multiple stages in real circuit applications due to reasons such as a reduced output swing and poorly defined logic states. Herein, we demonstrate ternary inverter circuits with near rail-to-rail swing and three distinct logic states by employing vdW p-n heterojunctions of single-walled carbon nanotubes (SWCNT) and MoS where the SWCNT layer completely covers the MoS layer.
View Article and Find Full Text PDFSci Adv
January 2025
Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-Based Electronics, School of Electronics, Peking University, Beijing 100871, China.
Multi-valued logics (MVLs) offer higher information density, reduced circuit and interconnect complexity, lower power dissipation, and faster speed over conventional binary logic system. Recent advancement in MVL research, particularly with emerging low-dimensional materials, suggests that breakthroughs may be imminent if multistates transistors can be fabricated controllably for large-scale integration. Here, a concept of source-gating transistors (SGTs) is developed and realized using carbon nanotubes (CNTs).
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