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Quantum dot

Colloidal quantum dots irradiated with a UV light. Differently sized quantum dots emit different colors of light due to quantum confinement.
Part of a series of articles on
Nanomaterials
Carbon nanotubes
Fullerenes
Other nanoparticles
Nanostructured materials

Quantum dots (QDs) or semiconductor nanocrystals are semiconductor particles a few nanometres in size with optical and electronic properties that differ from those of larger particles via quantum mechanical effects. They are a central topic in nanotechnology and materials science. When a quantum dot is illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conduction band. The excited electron can drop back into the valence band releasing its energy as light. This light emission (photoluminescence) is illustrated in the figure on the right. The color of that light depends on the energy difference between the discrete energy levels of the quantum dot in the conduction band and the valence band.[1]

Nanoscale semiconductor materials tightly confine either electrons or electron holes. The confinement is similar to a three-dimensional particle in a box model. The quantum dot absorption and emission features correspond to transitions between discrete quantum mechanically allowed energy levels in the box that are reminiscent of atomic spectra. For these reasons, quantum dots are sometimes referred to as artificial atoms,[2] emphasizing their bound and discrete electronic states, like naturally occurring atoms or molecules.[3][4] It was shown that the electronic wave functions in quantum dots resemble the ones in real atoms.[5]

Quantum dots have properties intermediate between bulk semiconductors and discrete atoms or molecules. Their optoelectronic properties change as a function of both size and shape.[6][7] Larger QDs of 5–6 nm diameter emit longer wavelengths, with colors such as orange, or red. Smaller QDs (2–3 nm) emit shorter wavelengths, yielding colors like blue and green. However, the specific colors vary depending on the exact composition of the QD.[8]

Potential applications of quantum dots include single-electron transistors, solar cells, LEDs, lasers,[9] single-photon sources,[10][11][12] second-harmonic generation, quantum computing,[13] cell biology research,[14] microscopy,[15] and medical imaging.[16] Their small size allows for some QDs to be suspended in solution, which may lead to their use in inkjet printing, and spin coating.[17] They have been used in Langmuir–Blodgett thin films.[18][19][20] These processing techniques result in less expensive and less time-consuming methods of semiconductor fabrication.

  1. ^ Shishodia, Shubham; Chouchene, Bilel; Gries, Thomas; Schneider, Raphaël (31 October 2023). "Selected I-III-VI2 Semiconductors: Synthesis, Properties and Applications in Photovoltaic Cells". Nanomaterials. 13 (21): 2889. doi:10.3390/nano13212889. ISSN 2079-4991. PMC 10648425. PMID 37947733.
  2. ^ Silbey, Robert J.; Alberty, Robert A.; Bawendi, Moungi G. (2005). Physical Chemistry (4th ed.). John Wiley & Sons. p. 835.
  3. ^ Ashoori, R. C. (1996). "Electrons in artificial atoms". Nature. 379 (6564): 413–419. Bibcode:1996Natur.379..413A. doi:10.1038/379413a0. S2CID 4367436.
  4. ^ Kastner, M. A. (1993). "Artificial Atoms". Physics Today. 46 (1): 24–31. Bibcode:1993PhT....46a..24K. doi:10.1063/1.881393.
  5. ^ Banin, Uri; Cao, YunWei; Katz, David; Millo, Oded (August 1999). "Identification of atomic-like electronic states in indium arsenide nanocrystal quantum dots". Nature. 400 (6744): 542–544. Bibcode:1999Natur.400..542B. doi:10.1038/22979. ISSN 1476-4687. S2CID 4424927.
  6. ^ Murray, C. B.; Kagan, C. R.; Bawendi, M. G. (2000). "Synthesis and Characterization of Monodisperse Nanocrystals and Close-Packed Nanocrystal Assemblies". Annual Review of Materials Research. 30 (1): 545–610. Bibcode:2000AnRMS..30..545M. doi:10.1146/annurev.matsci.30.1.545.
  7. ^ Brus, L. E. (2007). "Chemistry and Physics of Semiconductor Nanocrystals" (PDF). Retrieved 7 July 2009.
  8. ^ "Quantum Dots". Nanosys – Quantum Dot Pioneers. Retrieved 4 December 2015.
  9. ^ Huffaker, D. L.; Park, G.; Zou, Z.; Shchekin, O. B.; Deppe, D. G. (1998). "1.3 μm room-temperature GaAs-based quantum-dot laser". Applied Physics Letters. 73 (18): 2564–2566. Bibcode:1998ApPhL..73.2564H. doi:10.1063/1.122534. ISSN 0003-6951.
  10. ^ Lodahl, Peter; Mahmoodian, Sahand; Stobbe, Søren (2015). "Interfacing single photons and single quantum dots with photonic nanostructures". Reviews of Modern Physics. 87 (2): 347–400. arXiv:1312.1079. Bibcode:2015RvMP...87..347L. doi:10.1103/RevModPhys.87.347. ISSN 0034-6861. S2CID 118664135.
  11. ^ Eisaman, M. D.; Fan, J.; Migdall, A.; Polyakov, S. V. (2011). "Invited Review Article: Single-photon sources and detectors". Review of Scientific Instruments. 82 (7): 071101–071101–25. Bibcode:2011RScI...82g1101E. doi:10.1063/1.3610677. ISSN 0034-6748. PMID 21806165.
  12. ^ Senellart, Pascale; Solomon, Glenn; White, Andrew (2017). "High-performance semiconductor quantum-dot single-photon sources". Nature Nanotechnology. 12 (11): 1026–1039. Bibcode:2017NatNa..12.1026S. doi:10.1038/nnano.2017.218. ISSN 1748-3387. PMID 29109549.
  13. ^ Loss, Daniel; DiVincenzo, David P. (1998). "Quantum computation with quantum dots". Physical Review A. 57 (1): 120–126. arXiv:cond-mat/9701055. Bibcode:1998PhRvA..57..120L. doi:10.1103/PhysRevA.57.120. ISSN 1050-2947.
  14. ^ Michalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S. (2005). "Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics". Science. 307 (5709): 538–544. Bibcode:2005Sci...307..538M. doi:10.1126/science.1104274. PMC 1201471. PMID 15681376.
  15. ^ Wagner, Christian; Green, Matthew F. B.; Leinen, Philipp; Deilmann, Thorsten; Krüger, Peter; Rohlfing, Michael; Temirov, Ruslan; Tautz, F. Stefan (6 July 2015). "Scanning Quantum Dot Microscopy". Physical Review Letters. 115 (2): 026101. arXiv:1503.07738. Bibcode:2015PhRvL.115b6101W. doi:10.1103/PhysRevLett.115.026101. ISSN 0031-9007. PMID 26207484. S2CID 1720328.
  16. ^ Ramírez, H. Y.; Flórez, J.; Camacho, A. S. (2015). "Efficient control of coulomb enhanced second harmonic generation from excitonic transitions in quantum dot ensembles". Physical Chemistry Chemical Physics. 17 (37): 23938–23946. Bibcode:2015PCCP...1723938R. doi:10.1039/C5CP03349G. PMID 26313884. S2CID 41348562.
  17. ^ Coe-Sullivan, S.; Steckel, J. S.; Woo, W.-K.; Bawendi, M. G.; Bulović, V. (July 2005). "Large-Area Ordered Quantum-Dot Monolayers via Phase Separation During Spin-Casting". Advanced Functional Materials. 15 (7): 1117–1124. doi:10.1002/adfm.200400468. S2CID 94993172.
  18. ^ Xu, Shicheng; Dadlani, Anup L.; Acharya, Shinjita; Schindler, Peter; Prinz, Fritz B. (2016). "Oscillatory barrier-assisted Langmuir–Blodgett deposition of large-scale quantum dot monolayers". Applied Surface Science. 367: 500–506. Bibcode:2016ApSS..367..500X. doi:10.1016/j.apsusc.2016.01.243.
  19. ^ Gorbachev, I. A.; Goryacheva, I. Yu; Glukhovskoy, E. G. (June 2016). "Investigation of Multilayers Structures Based on the Langmuir-Blodgett Films of CdSe/ZnS Quantum Dots". BioNanoScience. 6 (2): 153–156. doi:10.1007/s12668-016-0194-0. ISSN 2191-1630. S2CID 139004694.
  20. ^ Achermann, Marc; Petruska, Melissa A.; Crooker, Scott A.; Klimov, Victor I. (December 2003). "Picosecond Energy Transfer in Quantum Dot Langmuir−Blodgett Nanoassemblies". The Journal of Physical Chemistry B. 107 (50): 13782–13787. arXiv:cond-mat/0310127. Bibcode:2003cond.mat.10127A. doi:10.1021/jp036497r. ISSN 1520-6106. S2CID 97571829.

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