Observation of Coulombic-Drag-Induced Instability in Short-Channel SiC Epitaxial Graphene Field-Effect Transistors

Graphene, as the first discovered 2D material, has attracted significant attention due to its unique linear dispersion and exceptional carrier mobility, which make graphene highly suitable for high-speed (GHz to THz range) electronic and optoelectronic devices, including amplifiers, detectors, and light sources [1]. In particular, the observation of the Coulombic drag (CD) effect and the negative differential conductivity associated with CD has opened new possibilities for THz detection and light emission. However, previous experimental demonstrations have been limited to Hall bar structures [2] and mechanically exfoliated separated double-layer graphene devices fabricated via layer stacking techniques [3]. These approaches present challenges for large-scale industrial applications and production. To overcome these limitations, we have previously demonstrated through theoretical analysis that NDC can also be realized in standard short-channel graphene field-effect transistors (GFETs) when the drain bias is applied at intermediate levels so as to make an inverted potential slope in the drain-side ungated region promoting the CD effect [4]. In this study, we experimentally demonstrate the observation of CD induced instability in SiC epitaxial GFETs, which are suitable for large-area film growth and fabrication without the need for mechanical transfer techniques.