Related Experiment Video
Updated: Feb 18, 2026
13:56
Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
8.4K
Bi2Se3 van der Waals Virtual Substrates for II-VI Heterostructures
Thor Axtmann Garcia1, Vasilios Deligiannakis2, Candice Forrester3
1Department of Chemistry, The City College of New York, 160 Convent Ave., New York, NY 10031, USA. The Chemistry Program of the Graduate Center of the City University of New York, 365 Fifth Ave., New York, NY 10016, USA.
Physica Status Solidi. B, Basic Solid State Physics : PSS
|November 25, 2017
Summary
Researchers developed high-quality ZnCdSe/ZnCdMgSe quantum wells on a novel Bi2Se3/CdTe virtual substrate. Substrate-free films show excellent photoluminescence, enabling new possibilities for ultra-thin electronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Optoelectronics
Background:
- Epitaxial growth of high-quality semiconductor quantum wells is crucial for advanced electronic and optoelectronic devices.
- Sapphire substrates are cost-effective but present challenges for growing specific heterostructures due to lattice mismatch.
- Virtual substrates offer a pathway to overcome lattice mismatch issues and enable growth on diverse materials.
Purpose of the Study:
- To report the growth and characterization of optical-quality ZnCdSe/ZnCdMgSe multiple quantum wells (MQWs).
- To investigate the feasibility of using an ultra-thin Bi2Se3/CdTe virtual substrate on sapphire.
- To explore substrate-independent epitaxy and the potential for ultra-thin electronics.
Main Methods:
- Epitaxial growth of MQWs using techniques like reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD).
- Photoluminescence (PL) spectroscopy at room temperature and 77 K to assess optical properties.
- Contactless electroreflectance (CER) spectroscopy for detailed electronic structure analysis.
Main Results:
- Achieved highly oriented (111) films of excellent quality, confirmed by RHEED and XRD.
- Observed strong photoluminescence emission at 77 K (2.407 eV) with narrow linewidths (56 meV), comparable to InP-grown structures.
- Demonstrated successful exfoliation of substrate-free films with preserved optical properties due to van der Waals bonding.
- CER measurements showed good agreement with simulations and revealed excited state levels.
Conclusions:
- The Bi2Se3/CdTe virtual substrate enables high-quality epitaxial growth of ZnCdSe-based MQWs on sapphire.
- Substrate-free films exhibit excellent optical properties, paving the way for novel device architectures.
- This approach offers a promising route for substrate-independent epitaxy and the development of ultra-thin electronics.
Related Concept Videos
03:24Hybridization of Atomic Orbitals I
68.1K
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...
68.1K
01:24Van der Waals Interactions
72.2K
Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion–dipole, dipole–dipole, and dispersion forces, collectively known as van der Waals forces.
72.2K
02:42Valence Bond Theory
11.4K
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...
11.4K
03:51Molecular Orbital Theory II
27.7K
Molecular Orbital Energy Diagrams
27.7K
02:38Valence Bond Theory and Hybridized Orbitals
31.1K
According to valence bond theory, a covalent bond results when: (1) an orbital on one atom overlaps an orbital on a second atom, and (2) the single electrons in each orbital combine to form an electron pair. The strength of a covalent bond depends on the extent of overlap of the orbitals involved. Maximum overlap is possible when the orbitals overlap on a direct line between the two nuclei.
A σ bond (single bond in a Lewis structure) is a covalent bond in which the electron density is...
A σ bond (single bond in a Lewis structure) is a covalent bond in which the electron density is...
31.1K
01:10Van der Waals Equation
6.5K
The ideal gas law is an approximation that works well at high temperatures and low pressures. The van der Waals equation of state (named after the Dutch physicist Johannes van der Waals, 1837−1923) improves it by considering two factors.
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
6.5K