A novel two-dimensional δ-InP3 monolayer with high stability, tunable bandgap, high carrier mobility and gas sensing of NO2
Based on ab initio density functional calculations and global optimization algorithm, here we propose a novel two-dimensional (2D) InP3 allotrope (named δ-InP3 monolayer), which has much lower formation energy and exfoliation energy than previous known β-InP3 monolayer. An indirect band gap of 0.51 eV is found in the δ-InP3 monolayer and could be easily tunable by adjusting the strains along its a direction. Our calculations reveal that this new InP3 allotrope exhibits good anisotropy properties, along with high electron carrier mobility. The electron mobility of the δ-InP3 monolayer can reach up to 2741 and 1751 cm2 V−1 s−1 along a and b direction, respectively. The absorption coefficients for δ-InP3 monolayer and bilayer are predicted up to the order of ~106 cm-1 in whole visible region. More interesting, the calculated results show that the δ-InP3 monolayer is a promising N-based gas sensor (especially for NO2 molecules), with high selectivity, sensitivity and good reversibility.