A First-Principle Study of Phosphorene-based Gas Sensors

This work presents a comprehensive study on adsorption properties of H2S, NH3, CO, and NO on phosphorene, by employing first-principle calculations. The optimized atomic sites, directions and the associated adsorption mechanisms are carefully analyzed. Transfer of charge between the gas molecule and the layer modifies the layer’s resistance. Therefore, by evaluating the resistance variation, the concentration of gas molecules can be determined. The results indicate that nitrogen-based molecules especially NO, show the highest sensitivity among the studied gases. In addition, strain effects on sensor characteristics and adsorption behavior are investigated. The optimal locations for the absorption of the gases and the mechanism of absorption energy under various strain conditions are analyzed. The results indicate that sensitivity increases with strain and significantly improves the selectivity of the sensor. The results show that both strained and unstrained phosphorene are suitable candidates for sensitive gas sensing applications.