Characterization of deep level defects present in mono-like, quasi-mono and multicrystalline silicon solar substrates. (27th January 2015)

• Record Type: Journal Article
• Authors: Pérez, E; García, H; Castán, H; Dueñas, S
• Is Part Of: Semiconductor science and technology. Volume 30:Number 3(2015:Mar.)
• Publication Date: 2015-01-27
• Subjects: Solar cell -- mono-cast -- defects -- thermal admittance spectroscopy -- LBIC; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/0268-1242/30/3/035011
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: Defects on mono-like (ml-Si), quasi-mono (qm-Si) and multicrystalline silicon solar cell substrates are studied in depth. Using the thermal admittance spectroscopy technique we found a single deep level with an activation energy between 213 and 224 meV and a capture cross section in the order of 10 −15 −10 −14 cm 2, in the case of ml-Si samples. The 271, 291 and 373 meV levels were found in qm-Si samples. The first one is associated with a capture cross section in the order of 10 −16 cm 2, the second one in the order of 10 −14, while the third one is associated, for the same magnitude, with a value in the order of 10 −12 cm 2 . Multicrystalline samples showed two tendencies in the Arrhenius plot fit associated with a deep level in each one. The activation energy of the first one ranges from 336 meV to 342 meV, and the capture cross sections are in the order of 10 −13 −10 −11 cm 2 . The values obtained for the second one are 251 and 171 meV, with the capture cross section values in the order of 10 −15 and 10 −18 cm 2, respectively. The nature of these defects is probably due to iron-based impurities in different complexes. Segregation into extended defects of Fe i or Fe i -V is the most probable cause of the deep levels with higher capture cross section value. Punctual complexes such as Fe i or Fe i -V2 are probably the reason for the deep levels with lower capture cross section value.