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| Andrew Fidler of Los Alamos National Laboratory examines an ultrafast photodetector used to measure quantum-dot carrier multiplication in real time. Courtesy: V Klimov |
Topics: Nanotechnology, Optics, Quantum Dots, Quantum Mechanics, Semiconductor Technology
Researchers at the Los Alamos National Laboratory in the US have developed the first ultrafast photodetector made from quantum dots that is capable of directly observing the extra electrons produced via “carrier multiplication” – the process by which multiple electrons are generated by a single photon. The result could help in the development of more efficient solar cells and new types of photo and radiation detectors.
When a conventional solar cell or photodetector absorbs a single photon, a single electron-hole pair (or exciton) is generated. However, in quantum dots (which are small pieces of semiconductor just several nanometres in size), electrons can efficiently interact with each other after they have absorbed light, generating multiple electrons from a single photon. This effect is known as carrier multiplication, and could help make cheaper and more efficient solar cells as well as new types of photodetectors.
Nanotechweb.org:
Ultrafast quantum-dot photodetector detects multiple electrons, Belle Dumé
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