Light from atomic defects: a 1–2 nm view
A tiny defect can reveal why a semiconductor emits light. Its atomic identity matters as much as its size.
- Journal publication
- First preprint
- Sources checked
A new publication, with a 2025 preprint
Huberich and colleagues published their study in Nature Nanotechnology on 5 November 2026. They connected individual defects in monolayer molybdenum disulfide (MoS₂) with their optical response. The first preprint appeared on 17 October 2025; the new date marks journal publication.[1] [2]
An electron and a hole form a pair
An excited electron can leave a hole that behaves like a positive charge. Their bound state is an exciton; recombination can release light. It is a quantum state in a crystal.[1]
Find the defect and read its light
The team used scanning tunnelling microscopy-induced luminescence: a fine probe injects charge while emitted light is collected. Two layers of hexagonal boron nitride (hBN) separated MoS₂ from graphene, reducing electronic coupling to the substrate.[1]
Inject charge with a probe and collect light
Top to bottom: MoS₂ monolayer, two hBN layers, graphene. Brown marks the defect and collected light schematically.
Different defects, different signals
Sulfur vacancies and oxygen substitutions suppressed pristine exciton emission in this set-up. Negatively charged carbon–hydrogen complexes hosted local defect emission, assigned to recombination of a conduction-band electron with a defect-bound hole. The spatial extent was 1–2 nm.
That scale describes localized emission as the probe moves. It is neither the emitted wavelength nor an atomic diameter.[1]
Make 1 nm equal to 1 cm
A nanometre is 10⁻⁹ m. Making it 1 cm gives a magnification of 10⁷ for every length below. The 80 µm hair is a teaching assumption.
80 µm = 80,000 nm; multiplying by 1 cm per nm gives 800 m. The emission extent becomes 1–2 cm. The common magnification preserves ratios; emission extent, DNA diameter and hair thickness remain different quantities.[1] [3] [4]
| Quantity | Original | Model |
|---|---|---|
| Emission extent | 1–2 nm | 1–2 cm |
| DNA helix diameter | About 2 nm | About 2 cm |
| Assumed hair thickness | 80 µm | 800 m |
An observation and the next engineering steps
Measurements required temperatures below 5 K and ultrahigh vacuum. The probe field also shifts emission energies. This does not establish a finished room-temperature single-photon device. The advance is connecting an identified atomic defect with its optical signal.[1]
Sources and scope
- Huberich et al. · Nature Nanotechnology
Final paper, Figs 3–5 and Methods: defect emission, 1–2 nm extent and conditions below 5 K.
- Huberich et al. · arXiv v1
First public version; a preprint, not the final interpretation.
- NIST · SI prefixes
Nano and micro definitions; the scale calculation and 80 µm hair are teaching assumptions.
- NHGRI · DNA Day, question 296
Approximate 2 nm double-helix diameter, distinct from molecular length.