title: Dipole-allowed direct band gap silicon superlattices.
abstract: Silicon is the most popular material used in electronic devices. However, its poor optical properties owing to its indirect band gap nature limit its usage in optoelectronic devices. Here we present the discovery of super-stable pure-silicon superlattice structures that can serve as promising materials for solar cell applications and can lead to the realization of pure Si-based optoelectronic devices. The structures are almost identical to that of bulk Si except that defective layers are intercalated in the diamond lattice. The superlattices exhibit dipole-allowed direct band gaps as well as indirect band gaps, providing ideal conditions for the investigation of a direct-to-indirect band gap transition. The fact that almost all structural portions of the superlattices originate from bulk Si warrants their stability and good lattice matching with bulk Si. Through first-principles molecular dynamics simulations, we confirmed their thermal stability and propose a possible method to synthesize the defective layer through wafer bonding.
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Oh
authors.affiliation: Korea Research Institute of Standards and Science, Daejeon 34113, Korea.|Center for In Silico Protein Science, School of Computational Science, Korea Institute for Advanced Study, Seoul 02455, Korea.
authors.forename: In-Ho
authors.initials: IH
authors.lastname: Lee
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
authors.forename: Sunghyun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Center for In Silico Protein Science, School of Computational Science, Korea Institute for Advanced Study, Seoul 02455, Korea.
authors.forename: Jooyoung
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
authors.forename: Kee Joo
authors.initials: KJ
authors.lastname: Chang