Tuning the Electronic Properties of Hexagonal Two-Dimensional GaN Monolayers via Doping for Enhanced Optoelectronic Applications

Abstract

We explore structural, electronic and magnetic properties of two-dimensional (2D) gallium nitride (GaN) monolayer (ML) doped with different elements belonging to the groups III−VI, using density-functionaltheory (DFT) with the Perdew-Burke-Ernzerhof (PBE) functional and the screened hybrid functional (HSE06) approaches as well as molecular dynamics (MD) simulations. Dopant interactions in Ga-and Nrich environments are investigated by varying their concentrations from 1.38% to 5.5%. Our calculations reveal that oxygen and aluminium impurities are the most preferred candidates under Ga-and N-rich conditions, respectively. The electronic structure studies indicate that dopants containing an even number of valence electrons introduce magnetic behavior with spin-polarized properties, or n-type conductivity with nonmagnetic features, depending on the stoichiometric III/V ratio during growth. Dopants with an odd number of valence electrons modify the GaN ML band structure from indirect to direct bandgap at the Γ point, depending on dopant types at different III/V ratios as well as substitutional site. The calculated charge transfer explains the dopants' influence on the band structure and bond nature. The HSE calculations of doped g-GaN MLs show a 0.23−1.48 eV increase in the band gaps including the spin polarized band structures when compared with their PBE values. MD calculations suggest high structural stability at high growth temperatures. Such dopant-induced modifications in structural and physical properties of 2D GaN ML could potentially allow use of this material in diverse electronic, optoelectronic and spintronic applications.

Theoretical research on p‐type doping two‐dimensional GaN based on first‐principles study

“…The value is smaller than experimental data because the PBE method will underestimate bandgap 8,9 . But it is still can predict the tendency of properties of 2D GaN before and after doping 18,20,21 . Figure 4 also shows that under different doping conditions, conduction‐band bottom and valence band top of two‐dimensional GaN doping model are both located at G point or F point, so they all have semiconductor properties of direct bandgap.…”

“…At the same time, due to the unique confinement structure, 2D GaN has new mechanical, 11,12 electronic and optical characteristics 13 . And they could be effectively controlled by chemical functionalization, 14 electric field, 15 doping, 16‐21 and adsorption 22‐25 . These make researchers have a great interest on 2D GaN, which is prospective for playing an important role in nano‐devices such as sterilization and water‐purification applications.…”

“…Zhao et al 20 have investigated magnetic properties of Mn‐doped 2D GaN. Alaal et al 21 have discussed magnetic and electronic characteristics when 2D GaN is doped with group III‐VI elements under N‐rich condition and Ga‐rich condition, respectively. However, there are no reports on p‐type doping technologies of buckled two‐dimensional GaN.…”

Modulating Electronic Structures of Armchair GaN Nanoribbons by Chemical Functionalization under an Electric Field Effect

“…Before presenting the results obtained through A-GaNNR investigations, it is worth noting that our calculations of the structural and electronic properties of a 2D GaN monolayer (ML) yields a Ga−N bond length of 1.86 Å, a lattice constant of 3.25 Å, and a band gap of 1.94 eV, in line with previously reported findings. 29,41 An A-GaNNR model is constructed by cutting such a GaN ML in a particular direction. We explore the electronic properties of bare A-GaNNRs in the absence of an external electric field, which are used for comparison, as will be discussed later.…”

“…The short N−O bond length confirms the presence of a double bond between the two atoms, and it matches the recently reported N−O bond length in the O-doped 2D GaN ML. 29 The distance (2.27 Å) between two O atoms (see Figure 4a) is wide enough to prevent bond formation between them, whereas a bond of 2.11 Å length is achieved between S atoms (see Figure 4b). Introduction of passivating atoms in the Oand S-A-GaNNRs can make them exhibit different electronic properties compared to those of bare A-GaNNRs.…”