Fractal field-effect transistors: Enhanced photodetection and fractal dependent resonances

TL;DR

This paper investigates fractal-shaped field-effect transistors (FETs) under specific boundary conditions, revealing fractal-dependent resonances and demonstrating improved photodetection capabilities with alternative fractal geometries.

Contribution

It introduces the study of fractal geometries in FETs under asymmetric boundary conditions and identifies fractal-dependent resonances and enhanced photodetector performance.

Findings

Resonant peaks at frequencies proportional to fractal recursion depth.

Resonant peaks depend on fractal dimensions of Sierpinski and alternative fractals.

Alternative fractal geometry outperforms Sierpinski carpet for photodetection.

Abstract

We study gated field effect transistors (FETs) with fractal geometries under Dyakonov and Shur asymmetric boundary conditions, where the source and drain span the left and right edges of the device respectively. An AC THz potential difference is applied between source and gate while a static source-drain voltage, rectified by the nonlinearities of FET electrons, is measured. We find, for a recursion depth, n, that resonant peaks in the potential integrated along the drain at ${\omega}_n = 3n{\omega}_0$ are amplified while all other are diminished. Additionally, we find the presence of peaks with frequencies dependent on the fractal dimensions of both the Sierpinski carpet and a similar alternative fractal. We then show the advantage of employing the alternative fractal as a superior geometry for the photodetector when compared to the Sierpinski carpet.