A high-frequency silicon-graphene-germanium barristor.
basic_science · Level V
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- Record sourced from PubMed, PMID 41951634.
- Also identified by DOI 10.1038/s41467-026-71447-3.
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Abstract
Realising ubiquitous environmental monitoring and smart sensing devices compatible with Internet of Things (IoT) and 6 G networks requires transistors with terahertz (THz) cutoff frequencies (f<sub>T</sub>) for efficient signal processing. However, the carrier transit time intrinsically limits conventional devices. Vertical two-dimensional (2D) base transistors offer a way to exceed this limit, yet interface losses typically suppress current gain, degrade high-frequency performance, and hinder THz operation. Here, we report a silicon-graphene-germanium barristor that overcomes these obstacles. Wafer-scale single-crystal graphene was epitaxially grown on germanium and integrated with silicon membranes, forming asymmetric Schottky barriers at the graphene-silicon and graphene-germanium interfaces. Using graphene's quantum capacitance, the asymmetric barriers enable distinct hot-carrier emission at both terminals and greatly increase the current gain, while graphene's atomic thickness minimises the perpendicular transit time. As a result, the device achieves a current gain up to 1.8 × 10<sup>7</sup> and an intrinsic f<sub>T</sub> up to 132 GHz, with modelling and simulation indicating scalability into the THz regime. These findings establish a promising high-frequency transistor paradigm for IoT sensors and systems.