High sensitivity refractive index sensor based on surface plasmon resonance with topological insulator

A high sensitivity refractive index sensor based on surface plasmon resonance ( SPR) with topological insulator ( Bi2Te3) has been proposed theoretically. It is demonstrated that the presented sensor exhibits an extremely great sensitivity enhancement with angular and wavelength-interrogation modes compared to conventional SPR sensor by covering the topological insulator ( Bi2Te3) on the gold thin film. In particular, the maximum sensitivity of wavelength-interrogated sensor can be further increased above 25% with 3 QL Bi2Te3 sheet. Moreover, in order to further increase the sensing performance, the few layers black phosphorus ( BP) and cytop film are covered on 1 QL ( a single Bi2Te3 crystal quintuple layer containing five layers of Bi and Te) Bi2Te3 to form a highly angular sensitive Bi2Te3-BP heterojunction, the maximum angular sensitivity can reach about 175 deg/RIU. Compared to the aforementioned Au-Bi2Te3 based SPR sensor, the sensitivity of this heterojunction-based SPR sensor is improved by 29%. With such improving performance, we believe that the configuration can be potentially used in the field of chemical and biological sensors in the future.