Effect of Stacking Orientation on the Electronic and Optical Properties of Polar 2D III-Nitride Bilayers

Abstract

Group-III nitrides are established commercial semiconductors that were recently synthesized in 2D form. We apply first-principles calculations to determine the electronic properties of polar hydrogen-passivated monolayers and bilayers of BN, AlN, GaN, and InN. We find that hydrogen-passivated AlN, GaN, and InN monolayers are stable under standard conditions. Our results indicate that antialigned bilayer orientations, which cancel the polarization fields, yield wide band gaps by quantum confinement. However, the band gaps are narrower in bilayers with aligned polarizations, due to the strong quantum-confined Stark effect. Strongly bound interlayer excitons form in structures with aligned polarizations due to the spatial separation of electron and hole wave functions on different monolayers. Our results demonstrate that the stacking orientation acts as an additional degree of freedom to tune the band gap of polar 2D bilayers, as well as to control the direct or interlayer nature of excitons for optoelectronic and excitonic applications.

Electronic Properties of Zn2V(1–x)NbxN3 Alloys to Model Novel Materials for Light-Emitting Diodes

“…Indeed, there are several reported studies of complex semiconductors belonging to the III–V family consisting of elements of group III (B, Al, Ga, and In) and group V (N, P, As, and Sb). − In particular, III–N alloys exhibit an ultrawide band gap due to the quantum confinement effect . Therefore, III–N alloys find applications in blue LEDs and ultraviolet optoelectronic devices − and in high-power electronic devices . Currently, InGa-N alloys are mostly used in industry due to their favorable electronic properties and established synthetic routes.…”

“… 1 − 13 In particular, III–N alloys exhibit an ultrawide band gap due to the quantum confinement effect. 14 Therefore, III–N alloys find applications in blue LEDs and ultraviolet optoelectronic devices 15 − 17 and in high-power electronic devices. 17 Currently, InGa-N alloys are mostly used in industry due to their favorable electronic properties and established synthetic routes.…”

“… 14 Therefore, III–N alloys find applications in blue LEDs and ultraviolet optoelectronic devices 15 − 17 and in high-power electronic devices. 17 Currently, InGa-N alloys are mostly used in industry due to their favorable electronic properties and established synthetic routes. However, these materials and their syntheses are expensive.…”