On the Prospect of Bioelectronics and Biosensors with the Novel Topological Phases of Matter

Abstract

Herein, the application capabilities of novel topological phases of matter in the field of bioelectronics and biosensors are assessed. Topological insulators could enable a novel generation of biosensors, exploiting the reduction of the low-frequency noise arising from the suppressed backscattering. Case-study examples of biosensors based on bismuth chalcogenides are discussed.Keywords: Topological insulators; Biosensors; Bioelectronics; Low-frequency noise OpinionBiosensors are devices of great importance for medical diagnostics, therapy monitoring, environmental science, biotechnology etc. The recent achievements in this fields are based on research on (i) materials and (ii) optimization of processes. By adopting standard solutions, further noteworthy advancement is unfeasible. Conversely, unexplored materials could provide interesting perspectives. The isolation of graphene in 2004 has paved the way for disruptive technologies based on twodimensional materials [1,2]. However, the absence of a band gap in graphene [3] impedes the achievement of a good ON/OFF ratio in nanodevices [4]. Following graphene, other two-dimensional van der Waals semiconductors, combining finite band gaps [5,6] and flexibility [7,8] are emerging in recent years as the most promising materials for nanoelectronics [4,9]. Topological insulators (TIs) are a class of innovative materials, whose physical properties have enormous potential for technological applications [10].TIs represent unique phases of matter with semiconducting bulk and conducting edge or surface states, immune to small perturbations, such as backscattering due to disorder. This stems from their peculiar band structure, which provides topological protection. Moreover, electron spin and momentum in topologically protected states are locked, thus enabling (i) the control of electron flow and (ii) the reduction of low-frequency noise in TI-based electronic devices [11]. As a matter of fact, the suppression of the backscattering of spin-polarized charge carriers of surface states, with the subsequent suppression of the fluctuation of mobility of surface-state charge carriers, could reduce electronic noise, so as to lower the detection limits of sensors below those already reported [11].Despite great interest from the scientific community, the huge potential of TIs for technological applications has been just started to be exploited [12]. Recent works report superb performance in TI-based nanodevices [13], also thanks to the progress in the control of single-crystal quality during the TI growth process. Among TIs, layered bismuth chalcogenides have attracted much attention since they can be easily grown by Bridgman-Stockbarger method and, moreover, since they show TI properties at room temperature [13].