Two-dimensional Al2O3 with ultrawide bandgap and large exciton binding energy for solar-blind ultraviolet photodetectors

New Al2O3 monolayers were predicted using density functional theory, and their stability, geometric structures, and mechanical, electronic, and optical properties were investigated. Among them, Te-Al2O3 with Pmmb space group was the most stable structure with markedly mechanical anisotropy. At the HSE06 level, Te-Al2O3 exhibited an ultra-wide indirect bandgap of 6.338 eV, which was verified to have a relatively reliable value by contrastive...