Adsorption behaviour of CF4 and COF2 gas on the GaN monolayer doped with Pt catalytic: A first-principles study

Abstract

GaN is an n-type semiconductor with a wide band gap and has broad application prospects in the field of gas detection. This paper uses the first-principles to study the adsorptions of five typical decomposition gases (CF4, COF2, CO2, O2 and N2) of SF6 alternative gas C4F7N by Pt doped GaN (Pt-GaN) monolayer and explores the feasibility of its application in the detection of decomposition components of C4F7N. The results show that the adsorption capacity of Pt-GaN to O2 (-0.263 eV) is greater than the other four gases (<-0.800 eV), and the adsorption mechanism of Pt-GaN as a resistive sensor is analysed in combination with its charge density difference and density of states represented by CF4 and COF2. On the other hand, the theoretical response values of these gases are obvious, amongst them, the theoretical recovery time of CF4 is almost 0, and the theoretical recovery time of COF2, CO2 and O2 at 498 K is only 2.2 s, 0 s and 0.149 s, respectively, indicating that Pt-GaN has industrial advantages in gas detection. After the five gases are adsorbed, the trend of work function change is different, which provides the possibility for Pt-GaN to be used as a field-effect transistor sensor to selectively detect gases All the content in this article provides theoretical guidance for Pt-GaN as a gas-sensitive material to realize the detection of C4F7N decomposition components.