Skip to main content Accessibility help
×
Home

Defects and Phonon Assisted Optical Transitions in Si Nanocrystals

  • G Allan (a1), C Delerue (a1) and M Lannoo (a1)

Abstract

Phonon-assisted and zero-phonon radiative transitions in nanoscale silicon quantum dots are studied using a new approach which combines a full calculation of the confined electronic eigenstates and vibration modes. We predict that the confinement, combined with the indirect bandgap of bulk silicon, must have several important consequences on the luminescence of a single silicon dot: i) a large broadening of the peaks, in the range of 10s of meV for a 3 nm dot, in spite of the atomic-like electronic structure of the dot ii) a great sensitivity of the spectrum to the size and the shape of the dot. We obtain that phonon-assisted transitions always dominate, even for size below 2 nm. Finally, we show that the radiative recombination in presence of an oxygen related surface defect (Si=O) is also assisted by optical phonons.

Copyright

References

Hide All
1 Brus, L., Appl.Phys. A 53, 465 (1991), and references therein.
2 Efros, AI. L. and Efros, A.L., Sov.Phys.Semicond. 16, 772 (1982); L. Brus, J. Chern. Phys. 80, 4403 (1984); D. J. Norris and M. G. Bawendi, Phys.Rev. B 53, 16338 (1996).
3 Brunner, K., Abstreiter, G., Bohm, G., Trankle, G. and Weimann, G., Phys.Rev.Lett. 73, 1138 (1994); S. A.Empedocles, D. J.Norris, and M. G.Bawendi, Phys.Rev.Lett. 27, 3873 (1996); D.Gammon, E. S.Snow, B. V.Shanabrook, D. S.Katzer, and D.Park, Phys.Rev.Lett. 76, 3005 (1996);
4 For a recent review, see Cullis, A. G., Canham, L. T., P. D. J. Calcott 82, 909 (1997) and in Theory of Optical Properties and Recombination Processes in Porous Silicon, edited by G. Amato,C. Delerue and H.-J. von Bardeleben, Vol. 5, Optoelectronic Properties of Semiconductors and Superlattices series, Gordon and Breach Science Publishers (1997)
5 Calcott, P.D.J., Nash, K.J., Canham, L.T., Kane, M.J. and Brumhead, D., J.Phys. Condens. Matter 5, L91 (1993). T.Suemoto, K.Tanaka, A.Nakajima, and T.Itakura, Phys.Rev.Lett. 70, 3659 (1993).
6 Brus, L., in Light Emission in Silicon. From Physics to Devices, edited by Lockwood, D., series Semiconductors and Semimetals, Vol.49, Academic Press, p. 303 (1998).
7 Hybertsen, M.S., Phys.Rev.Lett. 72, 1514 (1994).
8 Delerue, C., Allan, G. and Lannoo, M., Phys.Rev.B 48, 11024 (1993).
9 Zunger, A., MRS Bulletin 23, 35 (1998); C. Delerue, G. Allan and M. Lannoo, in Light Emission in Silicon. From Physics to Devices, edited by D. Lockwood, series Semiconductors and Semimetals, Vol.49, Academic Press, p. 253 (1998).
10 Martin, E., Delerue, C., Allan, G. and Lannoo, M., Phys.Rev.B 50, 18258 (1994).
11 Wang, L.W. and Zunger, A., J.Phys.Chem. 98, 2158 (1994).
12 Delley, B. and Steigmeier, E. F., Appl.Phys.Lett. 67, 2370 (1995).
13 Keating, P.N., Phys.Rev. 145, 637 (1966).
14 Dexter, D.L., in Solid State Physics, Advances in Research and Applications, edited by Seitz, F. and Turnbull, D. (Academic, New York, 1958), Vol.6, p. 360.
15 The splitting of the lowest excitonic state into singlet and triplet states due to the electron-hole exchange interaction lead to additional complications in the emission spectra [IC]. But as the phonons do not mix states with different spins, the phonons sidebands should be relatively unchanged.
16 Landsberg, P.T., in Recombination in Semiconductors, Cambridge University Press (1991).
17 Petit, J., Allan, G. and Lannoo, M., Phys.Rev.B 33, 8595 (1986).
18 Harrison, W.A., Electronic Structure and the Properties of Solids (Freeman, San Francisco, 1980).
19 Wolkin-Vakrat, M., Fauchet, P.M., Allan, G. and Delerue, C., Phys.Rev.Lett., to be published.

Defects and Phonon Assisted Optical Transitions in Si Nanocrystals

  • G Allan (a1), C Delerue (a1) and M Lannoo (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed