Gallium doped AlP monolayers: A promising architecture for gas sensing

Harmful gases like CO₂, SO, CO, SO₂, and H₂S can lead to serious environmental issues, making the development of effective sensors for their detection essential. This study used density functional theory (DFT)-based first-principles calculations to explore the structural, electronic, optical, and gas-sensing properties of a Ga-doped AlP monolayer towards the selected common pollutants, such as CO₂, SO, CO, SO₂, and H₂S. Van der Waals corrected simulations were employed to find the most effective and sensitive sites for gas adsorption. The results revealed that SO adsorption on a Ga-doped AlP monolayer exhibited a chemical nature, unlike the physical nature observed for the other gases based on the adsorption energy values which were −0.319, −0.712, −0.110, −0.990, and -0.332 for CO₂, SO₂, CO, SO, and H₂S gases respectively. Electron localization function (ELF) analysis of CO₂, SO₂, CO, and H₂S on a Ga-doped AlP monolayer showed delocalized electrons in the interlayer region, indicating that there was no chemical bonding between these gas molecules and the Ga-doped AlP monolayer. Moreover, the adsorption processes were found to affect the optical properties of a Ga-doped AlP monolayer. Overall, the results highlight the promising potential of a Ga-doped AlP monolayer as a gas sensor for the studied gases.