Electrical Transport Features of SiNWs Random Network on Si Support after Covalent Attachment of New Organic Functionalities

Abstract

Modification of the electrical transport of a random network of silicon nanowires assembled on nsilicon support, after silicon nanowires functionalization by chlorination/alkylation procedure , is here described and discussed. We show that the organic functionalities induce charge transfer at single SiNW and produce doping-like effect that is kept in the random network too. The SiNWs network also presents a surface recombination velocity lower than that of bulk silicon. Interestingly, the functionalized silicon nanowires/n-Si junctions display photo-yield and open circuit voltages higher than those including oxidized silicon nanowire networks. Electrical properties stability in time of junctions embedding propenyl terminated silicon nanowires network and transport modification after secondary functionalization is also shown. These results suggest a possible route for the integration of functionalized Si nanowires, although randomly distributed, in stable large area photovoltaic or molecule sensitive based devices.

A Non-Oxidative Approach Towards Hybrid Silicon Nanowire- Based Solar Cell Heterojunctions

“…Assuming a similar J0, which correspond to the removal of the tunneling oxide without changing the interface properties, the increase of Jsc would lead to a Voc gain of ∆Voc = kT/q.ln(Jsc,methyl/ Jsc,oxide) = kBT/q.ln(7.0/1.6) = 0.037 V. Regarding the observed gain of ∆Voc = 0.079 V, only a reduced surface recombination's (as measured by PY) and/or a favorable barrier formations (surface dipole) can establish consistency with the experimental data. The well passivation of methyl groups showed an impact in different devices as reported by Lewis as well[22,53,54].…”