We have investigated the behavior of one B impurity in the presence of dislocations, nanovoids and grain boundaries (GBs) in Si. Our study has been motivated by recent experiments on highly B-doped polycrystalline Si where a very significant thermoelectric power factor enhancement was observed. We study the influence of nanovoids on B diffusivity and activation in Si. We compare with the grain-boundary of pure tilt Si[001](120) poly-Si, where the presence of dislocations is dominant, similarly as in the case of nanovoids in c-Si. We performed DFT calculations to investigate minimum energy configurations, energy barriers and activation or deactivation of one B impurity in the proximity of the above structures. We found that, B preferably occupies substitutional lattice sites at the edge of the cavities. Thus the presence of small voids reduces its diffusivity and mobility, but the electrical activation of B is not significantly influenced. In the case of Si[001](120) GB, B is found to form Boron interstitials clusters in the close vicinity of a GB. The formation energy of those clusters is lower when the cluster is closer to center of the GB. Our results are in agreement with previously reported experimental data. It is provided insight to the effect of structural inhomogeneity on the dopant properties in Si structures that are currently of interest for thermoelectric applications.

Kanaki, A., Zianni, X., Narducci, D. (2015). Boron Diffusion in Silicon in the Presence of Grain Boundaries and Voids. MATERIALS TODAY: PROCEEDINGS, 2(2), 583-587 [10.1016/j.matpr.2015.05.079].

Boron Diffusion in Silicon in the Presence of Grain Boundaries and Voids

NARDUCCI, DARIO
Ultimo
2015

Abstract

We have investigated the behavior of one B impurity in the presence of dislocations, nanovoids and grain boundaries (GBs) in Si. Our study has been motivated by recent experiments on highly B-doped polycrystalline Si where a very significant thermoelectric power factor enhancement was observed. We study the influence of nanovoids on B diffusivity and activation in Si. We compare with the grain-boundary of pure tilt Si[001](120) poly-Si, where the presence of dislocations is dominant, similarly as in the case of nanovoids in c-Si. We performed DFT calculations to investigate minimum energy configurations, energy barriers and activation or deactivation of one B impurity in the proximity of the above structures. We found that, B preferably occupies substitutional lattice sites at the edge of the cavities. Thus the presence of small voids reduces its diffusivity and mobility, but the electrical activation of B is not significantly influenced. In the case of Si[001](120) GB, B is found to form Boron interstitials clusters in the close vicinity of a GB. The formation energy of those clusters is lower when the cluster is closer to center of the GB. Our results are in agreement with previously reported experimental data. It is provided insight to the effect of structural inhomogeneity on the dopant properties in Si structures that are currently of interest for thermoelectric applications.
Articolo in rivista - Articolo scientifico
Diffusivity; Energy barriers; Grain boundaries; Highly boron doped; Nanoporous; Polysilicon; Voids;
Diffusivity; Energy barriers; Grain boundaries; Highly boron doped; Nanoporous; Polysilicon; Voids
English
583
587
5
Kanaki, A., Zianni, X., Narducci, D. (2015). Boron Diffusion in Silicon in the Presence of Grain Boundaries and Voids. MATERIALS TODAY: PROCEEDINGS, 2(2), 583-587 [10.1016/j.matpr.2015.05.079].
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/10281/97287
Citazioni
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
Social impact