Related Experiment Video
Updated: Oct 17, 2025
11:10
Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model
Published on: May 23, 2018
12.1K
Tuning of Optical Phonons in α-MoO3-VO2 Multilayers
Sina Abedini Dereshgi1, Maria Cristina Larciprete2, Marco Centini2
1Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States.
ACS Applied Materials & Interfaces
|October 6, 2021
Summary
Researchers tuned optical phonons in alpha-molybdenum trioxide (α-MoO3) using vanadium dioxide (VO2) phase transitions. This work enables tunable infrared photonic devices for applications like camouflage and radiative cooling.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanophotonics
Background:
- Van der Waals (vdW) materials combined with vanadium dioxide (VO2) enable novel tunable photonic devices.
- Active tuning of optical phonons (OPhs) using far-field techniques is limited, despite VO2's phase change effects on near-field optical response.
Purpose of the Study:
- Investigate the tunability of OPhs in α-MoO3 within a multilayer structure incorporating VO2.
- Explore far-field tuning of OPhs for infrared photonic applications.
Main Methods:
- Fabrication of multilayer structures combining α-MoO3 and VO2.
- Experimental characterization of OPhs frequency and intensity.
- Theoretical verification using effective medium theory and dielectric models.
- Loss tangent analysis to understand spectral characteristics and substrate effects.
Main Results:
- Demonstrated frequency tuning of 2 cm⁻¹ for OPhs in the [100] direction of α-MoO3.
- Achieved 11% intensity tuning for OPhs in the [100] direction.
- Showcased 2 cm⁻¹ frequency tuning and 28% intensity tuning for OPhs in the [010] crystal direction.
- Validated experimental findings through simulations.
Conclusions:
- The study successfully demonstrates far-field tuning of OPhs in α-MoO3 using VO2 phase transitions.
- Findings provide a pathway for designing advanced tunable photonic devices for infrared applications.
- Potential applications include tunable camouflage and radiative cooling systems.
Related Concept Videos
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.9K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.9K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
2.0K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
2.0K
01:24IR Spectroscopy: Molecular Vibration Overview
3.3K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
3.3K
01:21IR Absorption Frequency: Hybridization
835
Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on the hybridization of the involved carbon atom and can be explained in terms of the s character of each hybridized atomic orbital.
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that...
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that...
835
01:28Standing Waves in a Cavity
1.1K
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
1.1K
01:04IR Absorption Frequency: Delocalization
992
Electron delocalization refers to the distribution of electrons across multiple atoms within a molecule rather than being confined to a single atom or bond. This phenomenon is common in systems with conjugated bonds—structures where alternating single and double bonds allow π-electrons to move freely across the network. The movement of electrons stabilizes the molecule and can affect various chemical properties, including vibrational frequencies observed in IR spectroscopy.
In IR...
In IR...
992