Strongly bound Mott-Wannier Excitons in GeS and GeSe monolayers

Abstract

The excitonic spectra of single layer GeS and GeSe are predicted by ab initio GW-Bethe Salpeter equation calculations. G 0 W 0 calculations for the band structures find a fundamental band gap of 2.85 eV for GeS and 1.70 eV for GeSe monolayer. However, excitons are tightly bound, specially in GeS at the Γ point, where the quasi-particle interactions are so strong that they shift the Γ exciton peak energy into the visible range and below the off-Γ exciton peak. The lowest energy excitons in both materials are excited by light along the zigzag direction and have exciton binding energies of 1.05 eV and 0.4 eV, respectively, but despite the strong binding, the calculated binding energies are in agreement with a Mott-Wannier model.

References in corpus (17)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Observation of tightly bound trions in monolayer MoS2
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Tunable Band Gap and Anisotropic Optical Response in Few-layer Black Phosphorus
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Isolation and characterization of few-layer black phosphorus
• Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of Exciton States
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• BerkeleyGW: A Massively Parallel Computer Package for the Calculation of the Quasiparticle and Optical Properties of Materials and Nanostructures
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Exciton Binding Energy of Monolayer WS2
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Phosphorene analogues: isoelectronic two-dimensional group-IV monochalcogenides with orthorhombic structure
• Direct imaging of the band profile in single layer $Mo{S}_2$ on graphite: quasiparticle energy gap, metallic edge states and edge band bending
• Polarization and valley switching in monolayer group-IV monochalcogenides
• Excitons in anisotropic 2D semiconducting crystals

Cited by in corpus (12)

• Large bulk photovoltaic effect and spontaneous polarization of single-layer monochalcogenides
• Colloquium: Physical properties of group-IV monochalcogenide monolayers
• Photostrictive two-dimensional materials in the monochalcogenide family
• Layered material GeSe and vertical GeSe/MoS2 p-n heterojunctions
• Experimental formation of monolayer group-IV monochalcogenides
• Group-IV monochalcogenide monolayers: two-dimensional ferroelectrics with weak intra-layer bonds and a phosphorene-like monolayer dissociation energy
• Triggering superconductivity, semiconducting states, and ternary valley structure in graphene via functionalization with Si-N layers
• Computational methods for 2D materials modelling
• Tunable Indirect-Direct Transition of Few-Layer SnSe via Interface Engineering
• Optical and Electronic Properties of SiTe_x(x=1,2) from First-Principles
• Localized Excitons in Defective Monolayer Germanium Selenide
• Shift current in 2D Janus Transition-Metal Dichalcogenides: the role of excitons