We show that the optical and electronic properties of nanocrystalline silicon can be efficiently tuned using impurity doping. In particular, we give evidence, by means of ab initio calculations, that by properly controlling the doping with either one or two atomic species, a significant modification of both the absorption and the emission of light can be achieved. We have considered impurities, either boron or phosphorous (doping) or both (codoping), located at different substitutional sites of silicon nanocrystals with size ranging from 1.1 to 1.8 nm in diameter. We have found that the codoped nanocrystals have the lowest impurity formation energies when the two impurities occupy nearest neighbor sites near the surface. In addition, such systems present band-edge states localized on the impurities, giving rise to a redshift of the absorption thresholds with respect to that of undoped nanocrystals. Our detailed theoretical analysis shows that the creation of an electron-hole pair due to light absorption determines a geometry distortion that, in turn, results in a Stokes shift between adsorption and emission spectra. In order to give a deeper insight into this effect, in one case we have calculated the absorption and emission spectra beyond the single-particle approach, showing the important role played by many-body effects. The entire set of results we have collected in this work give a strong indication that with the doping it is possible to tune the optical properties of silicon nanocrystals.

Iori, F., Degoli, E., Magri, R., Marri, I., Cantele, G., Ninno, D., et al. (2007). Engineering silicon nanocrystals: Theoretical study of the effect of codoping with boron and phosphorus. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 76(8) [10.1103/PhysRevB.76.085302].

Engineering silicon nanocrystals: Theoretical study of the effect of codoping with boron and phosphorus

PULCI, OLIVIA;
2007-01-01

Abstract

We show that the optical and electronic properties of nanocrystalline silicon can be efficiently tuned using impurity doping. In particular, we give evidence, by means of ab initio calculations, that by properly controlling the doping with either one or two atomic species, a significant modification of both the absorption and the emission of light can be achieved. We have considered impurities, either boron or phosphorous (doping) or both (codoping), located at different substitutional sites of silicon nanocrystals with size ranging from 1.1 to 1.8 nm in diameter. We have found that the codoped nanocrystals have the lowest impurity formation energies when the two impurities occupy nearest neighbor sites near the surface. In addition, such systems present band-edge states localized on the impurities, giving rise to a redshift of the absorption thresholds with respect to that of undoped nanocrystals. Our detailed theoretical analysis shows that the creation of an electron-hole pair due to light absorption determines a geometry distortion that, in turn, results in a Stokes shift between adsorption and emission spectra. In order to give a deeper insight into this effect, in one case we have calculated the absorption and emission spectra beyond the single-particle approach, showing the important role played by many-body effects. The entire set of results we have collected in this work give a strong indication that with the doping it is possible to tune the optical properties of silicon nanocrystals.
2007
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/03 - FISICA DELLA MATERIA
English
Con Impact Factor ISI
SI NANOCRYSTALS; POROUS SILICON; STIMULATED-EMISSION; GREENS-FUNCTION; OPTICAL GAIN; N-TYPE; P-TYPE; PHOTOLUMINESCENCE; SEMICONDUCTOR; GAPS
Iori, F., Degoli, E., Magri, R., Marri, I., Cantele, G., Ninno, D., et al. (2007). Engineering silicon nanocrystals: Theoretical study of the effect of codoping with boron and phosphorus. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 76(8) [10.1103/PhysRevB.76.085302].
Iori, F; Degoli, E; Magri, R; Marri, I; Cantele, G; Ninno, D; Trani, F; Pulci, O; Ossicini, S
Articolo su rivista
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/34536
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 85
  • ???jsp.display-item.citation.isi??? 78
social impact