May 24, 2024

Innovative Mixed-Dimensional Transistors Unleash High-Performance Multifunctional Electronic Devices

A research team led by materials scientists at City University of Hong Kong (CityU) has recently unveiled a groundbreaking strategy for developing versatile electronics with exceptional performance. By leveraging transistors constructed from mixed-dimensional nanowires and nanoflakes, the team has opened up avenues for simplified chip circuit design, promising versatility and low power dissipation in the realm of future electronics. The research findings, documented in the journal Device under the title “Multifunctional anti-ambipolar electronics enabled by mixed-dimensional 1D GaAsSb/2D MoS2 heterotransistors,” herald significant strides in the field.

As the downsizing of electronic devices, such as transistors, encounters a plateau, semiconductor fabrication encounters challenges. Scalability limitations in transistor and integrated circuit miniaturization pose hurdles in controllable and cost-effective semiconductor device production. Scaling down transistor size leads to increased current leakage and higher power dissipation, while intricate wiring networks contribute to elevated power consumption, underscoring the need for innovative solutions.

The emergence of multivalued logic (MVL) technology presents a promising avenue for combatting escalating power consumption in electronic devices. By reducing the number of transistor components and interconnections, MVL transcends the constraints of conventional binary logic systems, offering enhanced information density and lower power dissipation. Noteworthy efforts have been devoted to developing various multivalued logic devices, including anti-ambipolar transistors (AAT).

Anti-ambipolar transistors represent a distinctive category of transistors that facilitate the concurrent transport of both positive (holes) and negative (electron) charge carriers within the semiconducting channel. Although existing AAT-based devices predominantly rely on 2D or organic materials, which pose challenges in large-scale semiconductor device integration due to instability, their frequency characteristics and energy efficiency remain largely unexplored.

In a bid to overcome these limitations, a research team spearheaded by Professor Johnny Ho from CityU’s Department of Materials Science and Engineering embarked on a mission to develop anti-ambipolar device-driven circuits boasting enhanced information density, reduced interconnections, and explored frequency characteristics. Employing an advanced chemical vapor deposition technique, the team engineered a pioneering mixed-dimensional hetero-transistor amalgamating premium GaAsSb nanowires and MoS2 nanoflakes.

The newly devised anti-ambipolar transistors showcased exceptional performance, owing to the superior interfacial coupling and band-structure alignment properties of the GaAsSb/MoS2 junction. The hetero-transistor exhibited striking anti-ambipolar transfer characteristics with transconductance flipping, doubling the frequency in response to input analog circuit signals, thereby significantly slashing the number of devices required compared to conventional frequency multipliers in CMOS technology.

Professor Ho remarked, “Our mixed-dimensional, anti-ambipolar transistors can implement multi-valued logic circuits and frequency multipliers simultaneously, marking a pioneering advancement in the realm of anti-ambipolar transistor applications.” The multi-valued logic attributes simplify intricate wiring networks, curbing chip power dissipation. Reduced device dimensionality, combined with downscaled junction regions, renders the device swift and energy-efficient, resulting in elevated performance of digital and analog circuits.

1. Source: Coherent Market Insights, Public sources, Desk research
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