1/f Noise in Thin Films of Topological Insulator Materials

TL;DR

This study investigates low-frequency 1/f noise in thin films of topological insulators, revealing noise characteristics and implications for surface state conduction and device stability.

Contribution

It provides the first detailed analysis of 1/f noise in topological insulator thin films, highlighting noise behavior and potential for noise reduction in surface state conduction.

Findings

Noise spectral density is proportional to 1/f below 10 kHz.

Current fluctuations follow a quadratic dependence on drain-source current.

Results are relevant for designing low-noise topological insulator devices.

Abstract

We report results of investigation of the low-frequency excess noise in device channels made from topological insulators - a new class of materials with a bulk insulating gap and conducting surface states. The thin-film bismuth selenide samples were prepared by the "graphene-like" mechanical exfoliation from bulk crystals. The fabricated four-contact devices had linear current - voltage characteristics in the low-bias regime. The current fluctuations had the noise spectral density proportional to 1/f for the frequency f below 10 kHz. The noise spectral density followed the quadratic dependence on the drain - source current. The obtained data is important for planning transport experiments with topological insulators. We suggest that achieving the pure topological insulator phase with the current conduction through the "protected" surface states can lead to noise reduction via suppression of certain scattering mechanisms.