Documents disponibles écrits par cet auteur

Growth of dislocation clusters during directional solidification of multicrystalline silicon ingots / B. Ryningen in Acta materialia, Vol. 59 N° 20 (Décembre 2011) 

Public ISBD [article]  in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7703–7710 Titre : Growth of dislocation clusters during directional solidification of multicrystalline silicon ingots Type de document : texte imprimé Auteurs : B. Ryningen, Auteur ; G. Stokkan, Auteur ; M. Kivambe, Auteur Année de publication : 2012 Article en page(s) : pp. 7703–7710 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Crystal  growth  Dislocation  structure  Dislocations  Silicon  Directional  solidification Résumé : Highly detrimental dislocation clusters are frequently observed in lab-scale as well as industrially produced multicrystalline silicon ingots for solar cell applications. This paper presents an investigation of dislocation clusters and how they develop over the whole height of a pilot-scale ingot. A 12-kg ingot, cast in a pilot-scale directional solidification furnace using a standard slip cast silica crucible and standard coating containing silicon nitride powder, was studied with respect to dislocation clusters. Dislocation clusters originating from grain boundaries were identified and followed from an early stage to the top of the ingot. One possible model for growth and multiplication of the dislocations in the clusters during solidification where slip on the 〈1 1 0〉 system must be allowed is described in detail. Another possible mechanism is also discussed. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541100629X [article] Growth of dislocation clusters during directional solidification of multicrystalline silicon ingots [texte imprimé] / B. Ryningen, Auteur ; G. Stokkan, Auteur ; M. Kivambe, Auteur . - 2012 . - pp. 7703–7710. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7703–7710 Mots-clés : Crystal  growth  Dislocation  structure  Dislocations  Silicon  Directional  solidification Résumé : Highly detrimental dislocation clusters are frequently observed in lab-scale as well as industrially produced multicrystalline silicon ingots for solar cell applications. This paper presents an investigation of dislocation clusters and how they develop over the whole height of a pilot-scale ingot. A 12-kg ingot, cast in a pilot-scale directional solidification furnace using a standard slip cast silica crucible and standard coating containing silicon nitride powder, was studied with respect to dislocation clusters. Dislocation clusters originating from grain boundaries were identified and followed from an early stage to the top of the ingot. One possible model for growth and multiplication of the dislocations in the clusters during solidification where slip on the 〈1 1 0〉 system must be allowed is described in detail. Another possible mechanism is also discussed. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541100629X

Relationship between dislocation density and nucleation of multicrystalline silicon / G. Stokkan in Acta materialia, Vol. 58 N° 9 (Mai 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3223–3229 Titre : Relationship between dislocation density and nucleation of multicrystalline silicon Type de document : texte imprimé Auteurs : G. Stokkan, Auteur Année de publication : 2011 Article en page(s) : pp. 3223–3229 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Dislocations  Directional  solidification  Dendritic  growth  Grain  boundary  twin  Silicon Résumé : Dislocation density and crystal orientation were investigated for a set of multicrystalline silicon ingots grown in a pilot scale furnace. Both low and high dislocation density ingots were observed. The low dislocation density ingots showed a dominating orientation close to (2 1 1) in contrast to the high dislocation density ingots. The orientations are consistent with growth on dendritic crystals formed along the crucible bottom and dendritic crystals with an angle towards the melt, respectively. During crystal growth, the power that was dissipated to the crystallization furnace showed a marked drop shortly after the onset of crystallization for low dislocation density ingots, an indication of fast release of crystallization heat from dendritic growth. Ingots that were not dominated by a high dislocation density instead had a high occurrence of twinned areas. Favourable orientation of the [1 View the MathML source 0] vector in the growth plane is suggested to be the cause of growth dominated by multiple twin faceting. This favourable orientation existed for crystals grown from dendrites grown along the crucible bottom, and this is suggested as an explanation for why these crystals are dominated by multiple twins rather than dislocations. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541000056X [article] Relationship between dislocation density and nucleation of multicrystalline silicon [texte imprimé] / G. Stokkan, Auteur . - 2011 . - pp. 3223–3229. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3223–3229 Mots-clés : Dislocations  Directional  solidification  Dendritic  growth  Grain  boundary  twin  Silicon Résumé : Dislocation density and crystal orientation were investigated for a set of multicrystalline silicon ingots grown in a pilot scale furnace. Both low and high dislocation density ingots were observed. The low dislocation density ingots showed a dominating orientation close to (2 1 1) in contrast to the high dislocation density ingots. The orientations are consistent with growth on dendritic crystals formed along the crucible bottom and dendritic crystals with an angle towards the melt, respectively. During crystal growth, the power that was dissipated to the crystallization furnace showed a marked drop shortly after the onset of crystallization for low dislocation density ingots, an indication of fast release of crystallization heat from dendritic growth. Ingots that were not dominated by a high dislocation density instead had a high occurrence of twinned areas. Favourable orientation of the [1 View the MathML source 0] vector in the growth plane is suggested to be the cause of growth dominated by multiple twin faceting. This favourable orientation existed for crystals grown from dendrites grown along the crucible bottom, and this is suggested as an explanation for why these crystals are dominated by multiple twins rather than dislocations. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541000056X