Low-frequency 1/f noise in bismuth selenide Topological Insulators

Topological insulators is a newly discovered class of materials with the Dirac cone type dispersion at the surface and conventional band in the volume of the material. We present results of the study of the low-frequency excess noise in thin films made of Bi₂Se₃ topological insulator material. The films were prepared through mechanically cleavage from the bulk crystal via the “graphene-like” exfoliation procedure. We verified the quality and crystallinity of Bi₂Se₃ samples with the micro-Raman spectroscopy. Our fabricated devices have linear current voltage characteristics in the low bias region with the current fluctuation noise spectral density SI proportional to 1/f for frequency f less than 10 kHz. The noise spectral density SI showed the square law dependence on the source-drain current and changed from about ~10^-22 to 10^-18 A²/Hz as current changes form ~10^-7 to 10^-5 A. Our results can be used for understanding electron transport and trap dynamics, and for reducing low-frequency noise in topological insulator devices.