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oai:docta.ucm.es:20.500.14352/337022024-09-02T15:07:11Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc González Díaz, Germán author García Hemme, Eric author Olea Ariza, Javier author Pastor Pastor, David author Bailón, L. author Castán, H. author Dueñas, S. author García, H. author Pérez, E. author 2013-01-14 Intermediate band formation on silicon layers for solar cell applications was achieved by titanium implantation and laser annealing. A two-layer heterogeneous system, formed by the implanted layer and by the un-implanted substrate, was formed. In this work, we present for the first time electrical characterization results which show that recombination is suppressed when the Ti concentration is high enough to overcome the Mott limit, in agreement with the intermediate band theory. Clear differences have been observed between samples implanted with doses under or over the Mott limit. Samples implanted under the Mott limit have capacitance values much lower than the un-implanted ones as corresponds to a highly doped semiconductor Schottky junction. However, when the Mott limit is surpassed, the samples have much higher capacitance, revealing that the intermediate band is formed. The capacitance increasing is due to the big amount of charge trapped at the intermediate band, even at low temperatures. Ti deep levels have been measured by admittance spectroscopy. These deep levels are located at energies which vary from 0.20 to 0.28 eV below the conduction band for implantation doses in the range 10(13)-10(14) at./cm(2). For doses over the Mott limit, the implanted atoms become nonrecombinant. Capacitance voltage transient technique measurements prove that the fabricated devices consist of two-layers, in which the implanted layer and the substrate behave as an n(+)/n junction. 0021-8979 10.1063/1.4774241 https://hdl.handle.net/20.500.14352/33702 http://dx.doi.org/10.1063/1.4774241 http://scitation.aip.org Experimental verification of intermediate band formation on titanium-implanted silicon