title: Synthesis of Si nanosheets by a chemical vapor deposition process and their blue emissions.
abstract: We synthesized free-standing Si nanosheets (NSs) with a thickness of about <2 nm using a chemical vapor deposition process and studied their optical properties. The Si NSs were formed by the formation of frameworks first along six different <110> directions normal to [111], its zone axis, and then by filling the spaces between the frameworks along the <112> directions under high flow rate of processing gas. The Si NSs showed blue emission at 435 nm, and absorbance and photoluminescence (PL) excitation measurements indicate that enhanced direct band transition attributes to the emission. Time-resolved PL measurement, which showed PL emission at 435 nm and a radiative lifetime of 1.346 ns, also indicates the enhanced direct band gap transition in these Si NSs. These outcomes indicate that dimensionality of Si nanostructures may affect the band gap transition and, in turn, the optical properties.
authors.affiliation: School of Advanced Materials Science and Engineering, Yonsei University, Seoul 120-749, South Korea.
authors.forename: Ungkil
authors.initials: U
authors.lastname: Kim
authors.forename: Ilsoo
authors.initials: I
authors.lastname: Kim
authors.forename: Yonghee
authors.initials: Y
authors.lastname: Park
authors.forename: Ki-Young
authors.initials: KY
authors.lastname: Lee
authors.forename: Sang-Youp
authors.initials: SY
authors.lastname: Yim
authors.forename: Jae-Gwan
authors.initials: JG
authors.lastname: Park
authors.forename: Hong-Gyu
authors.initials: HG
authors.lastname: Ahn
authors.forename: Seung-Han
authors.initials: SH
authors.lastname: Park
authors.forename: Heon-Jin
authors.initials: HJ
authors.lastname: Choi
mesh_terms: D003116:Color; D003460:Crystallization / Q000379:methods*; D005740:Gases / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D005740:Gases; D046911:Macromolecular Substances; D012825:Silicon