Cu2O/SWNTs/n-Si heterojunctions for enhanced light harvesting

To improve the photovoltaic conversion efficiency of the SWNT/n-Si configuration, we introduce p-type wide bandgap semiconductor Cu₂O nanoparticles into the void space of the SWNT network. This has brought in several improvements for the SWNTs/n-Si junction: (1) increase light absorption in the original void space through the newly formed Cu₂O/n-Si junctions, the new part of the original SWNTs/n-Si junction; (2) enhance the utilization of photons at high energy (Cu₂O has a larger band gap > 2.0 eV); (3) improve charge transport through the Cu₂O/SWNT interface. It was found that the p-n heterojunctions form at the Cu₂O/n-Si interface can help photon absorption and separate the electron and hole pair of the excitons; the short circuit current of the Cu₂O-SWNT/n-Si devices increases with the thickness of the Cu₂O film.