Silicon nano-crystals (Si NCs) embedded in dielectric matrix are presently studied in view of their applications as tunable band-gap absorbers in all-silicon multi-junction photovoltaic cells. SiC/SiC:Si multilayers produced by Plasma Enhanced Chemical Vapor Deposition (PECVD) have been annealed to obtain Si NCs formation. Various experimental conditions (Si NCs size, doping level, crystallinity) have been considered. Macroscopical as well as microscopical electrical characterizations were carried out in order to understand the conduction mechanisms. Conductivity measurements as a function of temperature showed that the conductivity ranged from 10-6-10-3 S/cm and the activation energy range is 0.19-0.4 eV. Conductive-AFM was performed to identify the conductive path at nano-crystals level. The Si NCs showed enhanced conductivity with respect to the surrounding matrix. The measurements were correlated with optically determined crystallized fraction and with thermally activated transport properties.
Electrical properties of silicon nanodots/Si rich carbide systems for photovoltaic applications
PERANI, MARTINA;CAVALCOLI, DANIELA;
2013
Abstract
Silicon nano-crystals (Si NCs) embedded in dielectric matrix are presently studied in view of their applications as tunable band-gap absorbers in all-silicon multi-junction photovoltaic cells. SiC/SiC:Si multilayers produced by Plasma Enhanced Chemical Vapor Deposition (PECVD) have been annealed to obtain Si NCs formation. Various experimental conditions (Si NCs size, doping level, crystallinity) have been considered. Macroscopical as well as microscopical electrical characterizations were carried out in order to understand the conduction mechanisms. Conductivity measurements as a function of temperature showed that the conductivity ranged from 10-6-10-3 S/cm and the activation energy range is 0.19-0.4 eV. Conductive-AFM was performed to identify the conductive path at nano-crystals level. The Si NCs showed enhanced conductivity with respect to the surrounding matrix. The measurements were correlated with optically determined crystallized fraction and with thermally activated transport properties.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
