Effects of Two-Dimensional Material Thickness and Surrounding Dielectric Medium on Coulomb Interactions and Excitons

Abstract

We examine the impact of quantum confinement on the interaction potential between two charges in two-dimensional semiconductor nanosheets in solution. The resulting effective potential depends on two length scales, namely the thickness $d$ and an emergent length scale $d^{\ast }\equiv \epsilon d/{\epsilon }_{\text{sol}}$, where $\epsilon$ is the permittivity of the nanosheet and ${\epsilon }_{\text{sol}}$ is the permittivity of the solvent. In particular, quantum confinement, and not electrostatics, is responsible for the logarithmic behavior of the effective potential for separations smaller than $d$, instead of the one-over-distance bulk Coulomb interaction. Finally, we corroborate that the exciton binding energy also depends on the two-dimensional exciton Bohr radius $a_0$ in addition to the length scales $d$ and $d^{\ast }$ and analyze the consequences of this dependence.

arXiv comment10 pages, 10 figures

References in corpus (14)

• Atomically thin MoS2: A new direct-gap semiconductor
• Graphene Photonics and Optoelectronics
• Two-Dimensional Material Nanophotonics
• Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Scaling of excitons in carbon nanotubes
• Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields
• Excitons in van der Waals heterostructures: The important role of dielectric screening
• Tight-binding calculations of image charge effects in colloidal nanoscale platelets of CdSe
• The dielectric impact of layer distances on exciton and trion binding energies in van der Waals heterostructures
• The two-dimensional hydrogen atom revisited
• Screened potential of a point charge in a thin film
• Excitons and trions in monolayer transition metal dichalcogenides: A comparative study between the multiband model and the quadratic single-band model
• Explaining Observed Stability of Excitons in Highly Excited CdSe Nanoplatelets

Cited by in corpus (5)

• Observation of the quantized motion of excitons in CdSe nanoplatelets
• Biexcitons in Highly Excited CdSe Nanoplatelets
• Energy states of Rydberg excitons in finite crystals: From weak to strong confinement
• Cosmic string influence on a 2D hydrogen atom and its relationship with the Rytova-Keldysh logarithmic approximation in semiconductors
• Coulomb potential screening via charged carriers and charge-neutral dipoles/excitons in two-dimensional case