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

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.