DFT insights into the selective NH3 sensing mechanism of two dimensional ZnTe monolayer

Exploring novel NH3 sensing materials is crucial in chemical industries, fertilizing plants and medical fields. Herein, for the first time, the NH3 sensing behaviors and sensing mechanisms of two dimensional (2D) ZnTe monolayer are systematically investigated by density functional theory calculations. It is shown that 2D ZnTe monolayer exhibits excellent selective NH3 sensing properties. (220) crystal facet of ZnTe possesses a higher NH3 adsorption energy (−1.59 eV) and a larger charge transfer (0.195e) than (111) and (311) crystal facets. The positive charges could enhance NH3 sensing while the negative charges could reduce NH3 sensing. The NH3 adsorption strengths are significantly improved in O2 atmosphere while it is negligibly affected by N2 atmosphere and H2O atmosphere. Moreover, the presence of Zn vacancy and Fe, Co, Ni doping could improve the NH3 sensing of ZnTe. Additionally, the experimental results confirms that ZnTe possesses a low detection limit of 0.1 ppm NH3. These theoretical predictions and experimental results present a wide range of possibilities for the further development of ZnTe monolayer in NH3 sensing fields.