Effect of Nb Doping on Chemical Sensing Performance of Two-Dimensional Layered MoSe₂

Here, we report that Nb doping of two-dimensional (2D) MoSe₂ layered nanomaterials is a promising approach to improve their gas sensing performance. In this study, Nb atoms were incorporated into a 2D MoSe₂ host matrix, and the Nb doping concentration could be precisely controlled by varying the number of Nb₂O₅ deposition cycles in the plasma enhanced atomic layer deposition process. At relatively low Nb dopant concentrations, MoSe₂ showed enhanced device durability as well as NO₂ gas response, attributed to its small grains and stabilized grain boundaries. Meanwhile, an increase in the Nb doping concentration deteriorated the NO₂ gas response. This might be attributed to a considerable increase in the number of metallic NbSe₂ regions, which do not respond to gas molecules. This novel method of doping 2D transition metal dichalcogenide-based nanomaterials with metal atoms is a promising approach to improve the performance such as stability and gas response of 2D gas sensors.