Effects of uniaxial strain on the electronic properties of cuprous oxide single-crystal films

The analysis of strain on cuprous oxide (Cu2O) single-crystal films is a research gap that needs to be filled. Herein, for the first time, we investigate the effects of strain engineering on the (1 1 1)-oriented Cu2O single-crystal films via first-principles simulations. It is interesting to find that the band structure and electronic characteristics can be effectively controlled and regulated under uniaxial strain. The bandgap can be tuned from 0.828 eV to 0.775 eV and 0.818 eV, respectively, under tension and compression. On the other side, the impacts of the uniaxial strain on the carrier mobilities are simulated on the basis of deformation potential theory, indicating that compression is more conducive to promoting the carrier mobilities in comparison with tension. The electron mobility (μe) increases from 1.04 × 102 cm2∙V−1∙s−1 to 3.06 × 102 cm2∙V−1∙s−1 while the hole mobility (μh) increases from 0.34 × 102 cm2∙V−1∙s−1 to 1.83 × 102 cm2∙V−1∙s−1 under −3% compression ratio. Moreover, the effects of strain engineering on the carrier mobilities at different temperatures (100 ∼ 400 K) are also systematically investigated. This study advances our understanding of the physicochemical properties of Cu2O functional devices and provides theoretical guidance for their use in optoelectronic fields and electronic devices.