Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Energy-transfer pumping of semiconductor nanocrystals using an epitaxial quantum well


As a result of quantum-confinement effects, the emission colour of semiconductor nanocrystals can be modified dramatically by simply changing their size1,2. Such spectral tunability, together with large photoluminescence quantum yields and high photostability, make nanocrystals attractive for use in a variety of light-emitting technologies—for example, displays, fluorescence tagging3, solid-state lighting and lasers4. An important limitation for such applications, however, is the difficulty of achieving electrical pumping, largely due to the presence of an insulating organic capping layer on the nanocrystals. Here, we describe an approach for indirect injection of electron–hole pairs (the electron–hole radiative recombination gives rise to light emission) into nanocrystals by non-contact, non-radiative energy transfer from a proximal quantum well that can in principle be pumped either electrically or optically. Our theoretical and experimental results indicate that this transfer is fast enough to compete with electron–hole recombination in the quantum well, and results in greater than 50 per cent energy-transfer efficiencies in the tested structures. Furthermore, the measured energy-transfer rates are sufficiently large to provide pumping in the stimulated emission regime, indicating the feasibility of nanocrystal-based optical amplifiers and lasers based on this approach.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Schematic and optical properties of the hybrid quantum-well/nanocrystal structure.
Figure 2: Pump- and time-dependent emission from an isolated quantum well.
Figure 3: Experimental observations of QW–NC energy transfer.
Figure 4: Carrier relaxation and energy-transfer processes in the hybrid quantum-well/nanocrystal structure and a schematic of an electrically driven energy-transfer device.


  1. Alivisatos, A. P. Semiconductor clusters, nanocrystals, and quantum dots. Science 271, 933–937 (1996)

    Article  ADS  CAS  Google Scholar 

  2. Murray, C. B., Norris, D. J. & Bawendi, M. G. Synthesis and characterization of nearly monodisperse CdE (E = S, Se, Te) semiconductor nanocrystallites. J. Am. Chem. Soc. 115, 8706–8715 (1993)

    Article  CAS  Google Scholar 

  3. Bruchez, M., Moronne, M., Gin, P., Weiss, S. & Alivisatos, A. P. Semiconductor nanocrystals as fluorescent biological labels. Science 281, 2013–2016 (1998)

    Article  ADS  CAS  Google Scholar 

  4. Klimov, V. I. et al. Optical gain and stimulated emission in nanocrystal quantum dots. Science 290, 314–317 (2000)

    Article  ADS  CAS  Google Scholar 

  5. Next-Generation Lighting Initiative

  6. Colvin, V., Schlamp, M. & Alivisatos, A. Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymer. Nature 370, 354–357 (1994)

    Article  ADS  CAS  Google Scholar 

  7. Schlamp, M. C., Peng, X. G. & Alivisatos, A. P. Improved efficiencies in light emitting diodes made with CdSe(CdS) core/shell type nanocrystals and a semiconducting polymer. J. Appl. Phys. 82, 5837–5842 (1997)

    Article  ADS  CAS  Google Scholar 

  8. Coe, S., Woo, W.-K., Bawendi, M. & Bulovic, V. Electroluminescence from single monolayers of nanocrystals in molecular organic devices. Nature 420, 800–803 (2002)

    Article  ADS  CAS  Google Scholar 

  9. Dabbousi, B. O. et al. (CdSe)ZnS core-shell quantum dots: synthesis and characterization of a size series of highly luminescent nanocrystallites. J. Phys. Chem. 101, 9463–9475 (1997)

    Article  CAS  Google Scholar 

  10. Koleske, D. D. et al. Improved brightness of 380 nm GaN light emitting diodes through intentional delay of the nucleation island coalescence. Appl. Phys. Lett. 81, 1940–1942 (2002)

    Article  ADS  CAS  Google Scholar 

  11. Basko, D., La Rocca, G. C., Bassani, F. & Agranovich, V. M. Förster energy transfer from a semiconductor quantum well to an organic material overlayer. Eur. Phys. J. B 8, 353–362 (1999)

    Article  ADS  CAS  Google Scholar 

  12. Klimov, V. I. & McBranch, D. W. Femtosecond 1P-to-1S electron relaxation in strongly confined semiconductor nanocrystals. Phys. Rev. Lett. 80, 4028–4031 (1998)

    Article  ADS  CAS  Google Scholar 

  13. Xu, S., Mikhailovsky, A. A., Hollingsworth, J. A. & Klimov, V. I. Hole intraband relaxation in strongly confined quantum dots: Revisiting the “phonon bottleneck” problem. Phys. Rev. B 65, 045319 (2002)

    Article  ADS  Google Scholar 

  14. Klimov, V. I. Optical nonlinearities and ultrafast carrier dynamics in semiconductor nanocrystals. J. Phys. Chem. B 104, 6112–6123 (2000)

    Article  CAS  Google Scholar 

  15. Klimov, V. I., Mikhailovsky, A. A., McBranch, D. W., Leatherdale, C. A. & Bawendi, B. G. Quantization of multiparticle Auger rates in semiconductor quantum dots. Science 287, 1011–1013 (2000)

    Article  ADS  CAS  Google Scholar 

  16. Nakamura, S. & Fasol, G. The Blue Laser Diode: GaN Based Light Emitters and Lasers (Springer, Berlin Heidelberg, Germany, 1997)

    Book  Google Scholar 

  17. Wu, L. W. et al. Influence of Si-doping on the characteristics of InGaN-GaN multiple quantum-well blue light emitting diodes. IEEE J. Quantum Electron. 38, 446–450 (2002)

    Article  ADS  CAS  Google Scholar 

  18. Bidnyk, S. et al. High-temperature stimulated emission in optically pumped InGaN/GaN multiquantum wells. Appl. Phys. Lett. 72, 1623–1625 (1998)

    Article  ADS  CAS  Google Scholar 

Download references


This work was supported by Los Alamos LDRD Funds and the Office of Basic Energy Sciences, Office of Science, US Department of Energy. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the Department of Energy.

Author information

Authors and Affiliations


Corresponding authors

Correspondence to Marc Achermann or Victor I. Klimov.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Information

Calculation of the QW-NC energy transfer rate. (PDF 128 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Achermann, M., Petruska, M., Kos, S. et al. Energy-transfer pumping of semiconductor nanocrystals using an epitaxial quantum well. Nature 429, 642–646 (2004).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing