Unlocking a near 1 eV direct band gap, lattice-matched InN–As heterostructure with moist resistance for enhanced optoelectronic applications

Hexagonal indium nitride (InN) and arsenene (As) are two examples of experimentally validated two-dimensional (2D) materials that have been regarded promising for use in nanoelectronic devices. However, the current endeavor is centered on manipulating their electronic properties, specifically ways to induce the transition from an indirect to a direct band gap (<i>E</i>_g) in them. To overcome this challenge, we performed first-principles calculations to thoroughly examine the possibility of attaining a direct <i>E</i>_g compound by considering several stacking configurations of InN and As monolayers. The calculated binding energies (<i>E</i>_b) indicate that the stacking configuration with As positioned above In has higher stability compared to other stacking modes. It has a type-II band alignment with a direct <i>E</i>_g of 0.91 eV and a reasonable carrier mobility (<i>μ</i> ∼ 10³ cm² V^-1 s^-1), making it highly suited for absorbing visible light. As a result, improved optical absorption intensity and photo response range in the proposed heterostructure are also observed compared with individual InN and As monolayers.