Substrate effects on the exciton fine structure of black phosphorus quantum dots

Abstract

We study the size-dependent exciton fine structure in monolayer black phosphorus quantum dots (BPQDs) deposited on different substrates (isolated, Si and SiO${}_2$) using a combination of tight-binding method to calculate the single-particle states, and the configuration interaction formalism to determine the excitonic spectrum. We demonstrate that the substrate plays a dramatic role on the excitonic gaps and excitonic spectrum of the QDs. For reasonably high dielectric constants (${\epsilon }_{sub}\sim {\epsilon }_{Si}=11.7{\epsilon }_0$), the excitonic gap can be described by a single power law $E_X(R)=E_X^{(bulk)}+C/R^{\gamma }$. For low dielectric constants ${\epsilon }_{sub}\le {\epsilon }_{Si{O}_2}=3.9{\epsilon }_0$, the size dependence of the excitonic gaps requires the sum of two power laws $E_X(R)=E_g^{(bulk)}+A/R^n-B/R^m$ to describe both strong and weak quantum confinement regimes, where $A$, $B$, $C$, $\gamma$, $n$, and $m$ are substrate-dependent parameters. We also predict that the exciton lifetimes exhibit a strong temperature dependence, ranging between 2-8 ns (Si substrate) and 3-11 ns (SiO${}_2$ substrate) for QDs up 10 nm in size.

References in corpus (23)

• Black phosphorus field-effect transistors
• Rediscovering Black Phosphorus: A Unique Anisotropic 2D Material for Optoelectronics and Electronics
• Tunable Band Gap and Anisotropic Optical Response in Few-layer Black Phosphorus
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Direct Observation of Layer-Dependent Electronic Structure in Phosphorene
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Quasiparticle band structure and tight-binding model for single- and bilayer black phosphorus
• Quantum Hall Effect in Black Phosphorus Two-dimensional Electron Gas
• Tuning of the electronic and optical properties of single layer black phosphorus by strain
• Phosphorene nanoribbon as a promising candidate for thermoelectric applications
• Infrared fingerprints of few-layer black phosphorus
• Excitons in van der Waals heterostructures: The important role of dielectric screening
• Toward a realistic description of multilayer black phosphorus: from $GW$ approximation to large-scale tight-binding simulations
• Simple Screened Hydrogen Model of Excitons in Two-Dimensional Materials
• Excitons in anisotropic 2D semiconducting crystals
• Landau levels of single layer and bilayer phosphorene
• Anisotropic exciton Stark shift in black phosphorus
• Magneto-optical transport properties of monolayer phosphorene
• Electronic and magneto-optical properties of monolayer phosphorene quantum dots
• Polaronic effects in monolayer black phosphorus on polar substrates
• Theoretical investigation of electron-hole complexes in anisotropic two-dimensional materials
• Boundary conditions for phosphorene nanoribbons in the continuum approach
• Charging energy spectrum of black phosphorus quantum dots

Cited by in corpus (2)

• Dirac spectrum in gated multilayer black phosphorus nanoribbons
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