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Giant excitonic absorption and emission in two-dimensional group-III nitrides.

ABSTRACT: Absorption and emission of pristine-like semiconducting monolayers of BN, AlN, GaN, and InN are systematically studied by ab-initio methods. We calculate the absorption spectra for in-plane and out-of-plane light polarization including quasiparticle and excitonic effects. Chemical trends with the cation of the absorption edge and the exciton binding are discussed in terms of the band structures. Exciton binding energies and localization radii are explained within the Rytova-Keldysh model for excitons in two dimensions. The strong excitonic effects are due to the interplay of low dimensionality, confinement effects, and reduced screening. We find exciton radiative lifetimes ranging from tenths of picoseconds (BN) to tenths of nanoseconds (InN) at room temperature, thus making 2D nitrides, especially InN, promising materials for light-emitting diodes and high-performance solar cells.

SUBMITTER: Prete MS

PROVIDER: S-EPMC7329854 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Giant excitonic absorption and emission in two-dimensional group-III nitrides.

Prete Maria Stella MS Grassano Davide D Pulci Olivia O Kupchak Ihor I Olevano Valerio V Bechstedt Friedhelm F

Scientific reports 20200701 1

Absorption and emission of pristine-like semiconducting monolayers of BN, AlN, GaN, and InN are systematically studied by ab-initio methods. We calculate the absorption spectra for in-plane and out-of-plane light polarization including quasiparticle and excitonic effects. Chemical trends with the cation of the absorption edge and the exciton binding are discussed in terms of the band structures. Exciton binding energies and localization radii are explained within the Rytova-Keldysh model for exc ...[more]

PMID: 32612146

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