Hybrid materials composed of different functional structural units offer the possibility of tuning both the thermal and electronic properties of a material independently. Using quantum mechanical calculations, we investigate the change in the electronic and thermoelectric transport properties of graphene and hydrogen-terminated carbon nanoribbons (CNRs) when these are placed on the SrTiO3 (001) surface (STO). We predict that both p-type and n-type composite materials can be achieved by coupling graphene/CNR to different surface terminations of STO. We show that the electronic properties of graphene and CNR are significantly altered on SrO-terminated STO but are preserved upon interaction with TiO2-terminated STO and that CNRs possess distinct electronic states around the Fermi level because of their quasi-one-dimensional nature, leading to a calculated Seebeck coefficient much higher than that of a pristine graphene sheet. Moreover, our calculations reveal that in the TiO2-SrTiO3/CNR system there is a favorable electronic level alignment between the CNR and STO, where the highest occupied molecular orbital of the CNR is positioned in the middle of the STO band gap, resembling n-type doping of the substrate. Our results offer design principles for guiding the engineering of future hybrid thermoelectric materials and, more generally, nanoelectronic materials comprising oxide and graphitic components.
Baran, J. D., Eames, C., Takahashi, K., Molinari, M., Islam, M. S., & Parker, S. C. (2017). Structural, Electronic, and Transport Properties of Hybrid SrTiO3-Graphene and Carbon Nanoribbon Interfaces. Chemistry of Materials, 29(17), 7364-7370. https://doi.org/10.1021/acs.chemmater.7b02253, https://doi.org/10.1021/acs.chemmater.7b02253