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100 mW deep-ultraviolet emission from aluminium-nitride-based quantum wells pumped by an electron beam

Nature Photonics volume 4, pages 767–770 (2010)Cite this article

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Abstract

Ultraviolet light sources, represented by excimer and mercury lamps, are currently used for various applications, including water purification/sterilization, biotechnology, photolithography and surface modification. However, they have the disadvantages of limited portability, low emission efficiency and the presence of harmful constituents. Finding a compact, efficient and environmentally friendly alternative ultraviolet light source is therefore of considerable technological interest. Aluminium-nitride-based semiconductors show promise as materials for this purpose1,2,3,4,5,6,7,8,9,10,11,12,13, but because of difficulties in controlling electronic conductivity, in light-emitting diodes are hampered by low external quantum efficiencies. Here, we use an electron-beam pumping technique, demonstrating an output of 100 mW and a record power efficiency of ∼40% from AlxGa1−xN/AlN quantum wells emitting at ∼240 nm. This achievement is attributed to carrier confinement within the high-quality quantum wells, as well as the appropriate design of sample structures for electron-beam pumping, and may be a milestone in the path to realizing next-generation ultraviolet light sources with great ecological and economic benefits.

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Figure 1: Fundamental optical properties.
Figure 2: Schematic configuration of EB pumping experiments.
Figure 3: CL spectrum with photodiode responsivity.
Figure 4: Electron penetration.
Figure 5: Electron beam pumping.

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References

  1. Taniyasu, Y., Kasu, M. & Makimoto, T. An aluminium nitride light-emitting diode with a wavelength of 210 nanometres. Nature 441, 325–328 (2006).

    Article  ADS  Google Scholar 

  2. Khan, A., Balakrishnan, K. & Katona, T. Ultraviolet light-emitting diodes based on group three nitrides. Nature Photon. 2, 77–84 (2008).

    Article  ADS  Google Scholar 

  3. Li, J., Nam, B., Nakarmi, M. L., Lin, J. Y. & Jiang, H. X. Band structure and fundamental optical transitions in wurtzite AlN. Appl. Phys. Lett. 83, 5163–5165 (2003).

    Article  ADS  Google Scholar 

  4. Shatalov, M. et al. Efficiency of light emission in high aluminum content AlGaN quantum wells. J. Appl. Phys. 105, 073103 (2009).

    Article  ADS  Google Scholar 

  5. Bhattacharyya, A., Moustakas, T. D., Zhou, L., Smith, D. J. & Hug, W. Deep ultraviolet emitting AlGaN quantum wells with high internal quantum efficiency. Appl. Phys. Lett. 94, 181907 (2009).

    Article  ADS  Google Scholar 

  6. Banal, R. G., Funato, M. & Kawakami, Y. Initial nucleation of AlN grown directly on sapphire substrates by metalorganic vapor phase epitaxy. Appl. Phys. Lett. 92, 241905 (2008).

    Article  ADS  Google Scholar 

  7. Banal, R. G., Funato, M. & Kawakami, Y. Growth characteristics of AlN on sapphire substrates by modified migration enhanced epitaxy. J. Cryst. Growth 311, 2834–2836 (2009).

    Article  ADS  Google Scholar 

  8. Banal, R. G., Funato, M. & Kawakami, Y. Characteristic of high Al-content AlGaN/AlN quantum wells fabricated by modified migration enhanced epitaxy. Phys. Status Solidi c 7, 2111–2114 (2010).

    Article  Google Scholar 

  9. Banal, R. G., Funato, M. & Kawakami, Y. Optical anisotropy in [0001]-oriented AlxGa1–xN/AlN quantum wells (x>0.69). Phys. Rev. B 79, 121308(R) (2009).

    Article  ADS  Google Scholar 

  10. Fujioka, A., Misaki, T., Murayama, T., Narukawa, Y. & Mukai, T. Improvement in output power of 280-nm-deep ultraviolet light-emitting diode by using AlGaN multi quantum wells. Appl. Phys. Express 3, 041001 (2010).

    Article  ADS  Google Scholar 

  11. Pernot, C. et al. Improved efficiency of 255–280 nm AlGaN-based light-emitting diodes. Appl. Phys. Express 3, 061004 (2010).

    Article  ADS  Google Scholar 

  12. Hirayama, H. et al. 222–282 nm AlGaN and InAlGaN-based deep-UV LEDs fabricated on high-quality AlN on sapphire. Phys. Status Solidi a 206, 1176–1182 (2009).

    Article  ADS  Google Scholar 

  13. Hirayama, H., Tsukada, Y., Maeda, T. & Kamata, N. Marked enhancement in the efficiency of deep-ultraviolet AlGaN light-emitting diodes by using a multi quantum-barrier electron blocking layer. Appl. Phys. Express 3, 031002 (2010).

    Article  ADS  Google Scholar 

  14. Narukawa, Y. et al. Ultra-high efficiency white light emitting diodes. Jpn J. Appl. Phys. 45, L1084–L1086 (2006).

    Article  ADS  Google Scholar 

  15. Yamada, M. et al. InGaN-based near-ultraviolet and blue-light-emitting diodes with high external quantum efficiency using a patterned sapphire substrate and a mesh electrode. Jpn J. Appl. Phys. 41, L1431–L1433 (2002).

    Article  ADS  Google Scholar 

  16. Madelung, O. Semiconductors: Data Handbook 3rd edn, Ch. 2 (Springer, 2003).

    Google Scholar 

  17. Watanabe, K., Taniguchi, T., Niiyama, T., Miya, K. & Taniguchi, M. Far-ultraviolet plane-emission handheld device based on hexagonal boron nitride. Nature Photon. 3, 591–594 (2009).

    Article  ADS  Google Scholar 

  18. Miyake, H. et al. Fabrication of deep-ultraviolet light source using AlGaN on AlN/sapphire. 8th International Symposium on Semiconductor Light Emitting Devices (ISSLED), E2 (Beijing, 2010).

  19. Göbel, E. O., Jung, H., Kuhl, J. & Ploog, K. Recombination enhancement due to carrier localization in quantum well structures. Phys. Rev. Lett. 51, 1588–1591 (1983).

    Article  ADS  Google Scholar 

  20. Drouin, D. et al. CASINO V2.42—a fast and easy-to-use modeling tool for scanning electron microscopy. Scanning 29, 92–101 (2007).

    Article  Google Scholar 

  21. Miller, R. C., Kleinman, D. A., Nordland, W. A. Jr & Gossard, A. C. Luminescence studies of optically pumped quantum wells in GaAs–AlxGa1–xAs multilayer structures. Phys. Rev. B 22, 863–871 (1980).

    Article  ADS  Google Scholar 

  22. Saito, T. et al. UV/VUV photodetectors using group III-nitride semiconductors. Phys. Status Solidi c 6, S658–S661 (2009).

    Article  ADS  Google Scholar 

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Acknowledgements

The authors would like to thank T. Hitora (president CEO, AlGaN K.K., Japan) for his support regarding the AlGaN photodiodes. This work was partly supported by a Grant-in-Aid for Scientific Research (18069007) and the Global Center-of-Excellence (G-COE) Programme of the Ministry of Education, Culture, Sports, Science and Technology of Japan.

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Authors and Affiliations

  1. Department of Electronic Science and Engineering, Kyoto University, Kyoto, 615-8510, Japan

    Takao Oto, Ryan G. Banal, Mitsuru Funato & Yoichi Kawakami

  2. SSLS Development Department, Ushio Inc., Himeji, Hyogo, 671-0224, Japan

    Ken Kataoka

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  1. Takao Oto
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Contributions

Y.K. supervised the project. R.G.B. performed crystal growth and PL measurements. Y.K, M.F., T.O. and K.K. conceived and designed the CL experiments. T.O. and K.K. performed the experiments, and T.O. carried out the simulation. All authors participated in the analyses, discussions of the data and writing the paper.

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Correspondence to Yoichi Kawakami.

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Oto, T., Banal, R., Kataoka, K. et al. 100 mW deep-ultraviolet emission from aluminium-nitride-based quantum wells pumped by an electron beam. Nature Photon 4, 767–770 (2010). https://doi.org/10.1038/nphoton.2010.220

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