Synthesis and humidity sensing behaviour of Cu-intercalated Bi2Se3 topological insulator single crystals

Abstract

Single crystals of CuxBi2Se3 (X=0, 0.1) topological insulator (TI) synthesized by using self -flux method and has been utilized for investigation of room temperature humidity sensing study. The samples are thoroughly characterized using XRD, FESEM, Raman, etc. The Cu0.1Bi2Se3 single crystal exhibits highest sensitivity (∼276%), response/recovery time (∼25s.), negligible hysteresis (<1%) and excellent stability within 8-97% RH range at room temperature. Freundlich isotherm model shows improved adsorption parameters (k and α) for CuXBi2Se3 (X=0.1) over entire RH region confirming the improved sensing performance of Bi2Se3 TIs with Cu intercalation. The excellent humidity sensitivity observed in TI's is attributed to Grotthuss mechanism considering the availability and distribution of available adsorption sites. This report suggests potential application of TI's as promising candidate for the fabrication of next generation humidity sensors. © 2019 Author(s).