New stable ultrawide bandgap As₂O₃ semiconductor materials

Ultrawide band gap materials have numerous potential applications in deep ultraviolet optoelectronics, as well as next-generation high-power and radio frequency electronics. Through the first-principles calculations based on density functional theory calculations, we demonstrate that the As2O3 bulk and monolayer structures have excellent energetic, mechanical, and thermal stabilities. The bulk and monolayer of As2O3 come in two distinct structures, namely st1-As2O3, and st2-As2O3. We show that the st1-As2O3 and st2-As2O3 monolayer and bilayer could be mechanically exfoliated from their bulk material and found that the cleavage energy values are significantly lower than those reported for similarly layered materials. By performing Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE06) band structure calculations, we found that the bulk and monolayers of As2O3 structures exhibit wide (PBE) and ultra-wide (HSE06) indirect band gaps. We further evaluate the As2O3 layered thickness-dependent band gaps and found that band gap decreases uniformly as the number of st1-As2O3 and st2-As2O3 layers increases. Our findings demonstrate the potential of the As2O3 structures for the future design of ultra-wide band gap semiconductor electronic devices.