Related Experiment Video
Updated: Jun 20, 2025
08:12
Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
Published on: September 8, 2017
9.5K
Tunable Exciton Polaritons in Band-Gap Engineered Hexagonal Boron Nitride
Pedro Ninhos1, Christos Tserkezis1, N Asger Mortensen1,2
1POLIMA─Center for Polariton-driven Light-Matter Interactions, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
ACS Nano
|July 23, 2024
Summary
Hexagonal boron nitride (hBN) superlattices offer tunable excitons in the UV range. This platform enables control over effective mass, band gap, and exciton binding energies for advanced polaritonics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Two-dimensional materials like hexagonal boron nitride (hBN) are crucial for advanced electronic and optical applications.
- Excitons in two-dimensional materials exhibit unique quantum properties that can be manipulated for novel devices.
Purpose of the Study:
- To investigate the formation of electrostatically tunable excitons in hexagonal boron nitride (hBN) under a superlattice potential.
- To explore the impact of superlattice potentials on the electronic and optical properties of hBN for UV applications.
Main Methods:
- Analytical and numerical methods were employed to study the system.
- The study involved calculating excitonic energy levels and optical conductivity.
- Absorption spectra were computed to analyze optical properties.
Main Results:
- An external superlattice potential was shown to renormalize the effective mass tensor, leading to anisotropic effective masses.
- The band gap was found to be renormalized and reduced, and exciton binding energies decreased.
- The system demonstrated the ability to mimic a grid polarizer, with results depending on a single dimensionless parameter.
Conclusions:
- One-dimensional hBN superlattices provide a tunable platform for excitons in the near- and mid-ultraviolet (UV) range.
- The tunable properties make hBN superlattices suitable for fine-tuned polaritonics in the UV to visible spectral range.
- This research opens avenues for novel optoelectronic devices operating in the UV spectrum.
More Related Videos
13:56Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
7.6K
10:35Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
Published on: September 26, 2014
12.3K
Related Concept Videos
01:01Energy Bands in Solids
817
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
817
02:35Band Theory
15.1K
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
15.1K
03:24Hybridization of Atomic Orbitals I
46.8K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
46.8K
02:42Valence Bond Theory
8.5K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.5K
03:02Colors and Magnetism
11.6K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.6K
01:20Types of Semiconductors
583
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
583