This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In a new Physical Review Letters study, researchers have demonstrated that bending diamond nanostructures can tune the light they emit without doping. Diamond is an ultrawide bandgap semiconductor with high carrier mobility, high thermal conductivity, deep-ultraviolet light emission and stable single-photon emission.
These properties make it a potential candidate for next-generation electronic and optoelectronic devices. However, properties such as its bandgap and light emission are difficult to tune because doping in diamond poses limitations. Elastic strain engineering, which stretches or compresses a material without permanently deforming it, has emerged as an alternative.
But controlling strain at the nanoscale is difficult, and light emission in diamond depends on lattice vibrations called phonons, which makes the process complex. The researchers in this study bent diamond nanoribbons to create a strain gradient, a gradual variation from compression to tension across the ribbon. Their aim was to study how the strain affects the emitted light.
Phys.org spoke with the corresponding author, Lin Yang from Peking University. "My research explores how mechanical deformation changes atomic vibrations and energy transport in materials. This led us to ask whether those changes could also help control light emission in diamond ...
The ability to bend nanoscale diamonds opened an opportunity to explore that question," said Yang. Semiconductors are broadly classified into two categories based on their bandgap, the energy gap between the valence and conduction bands: direct and indirect. In direct semiconductors, electrons can drop straight across the bandgap and emit a photon with energy equal to the bandgap.
In indirect semiconductors like diamond, the electron must also change momentum, which a photon cannot supply, so it needs help from lattice vibrations called phonons. "Phonons are packets of collective atomic vibration within a crystal ... These vibrations help determine which light-emitting transitions can occur," explained Yang.
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