title: White light emission and optical gains from a Si nanocrystal thin film.
abstract: We report a Si nanocrystal thin film consisting of free-standing Si nanocrystals, which can emit white light and show positive optical gains for its red, green and blue (RGB) components under ultraviolet excitation. Si nanocrystals with ϕ = 2.31 ± 0.35 nm were prepared by chemical etching of Si powder, followed by filtering. After being mixed with SiO2 sol-gel and thermally annealed, a broadband photoluminescence (PL) from the thin film was observed. The RGB ratio of the PL can be tuned by changing the annealing temperature or atmosphere, which is 1.00/3.26/4.59 for the pure white light emission. The origins of the PL components could be due to differences in oxygen-passivation degree for Si nanocrystals. The results may find applications in white-light Si lasing and Si lighting.
authors.affiliation: Department of Optical Science and Engineering, and Shanghai Ultra-Precision Optical Manufacturing Engineering Centre, Fudan University, Shanghai 200433, People's Republic of China.
authors.forename: Dong-Chen
authors.initials: DC
authors.lastname: Wang
authors.forename: Hong-Chen
authors.initials: HC
authors.lastname: Hao
authors.forename: Jia-Rong
authors.initials: JR
authors.lastname: Chen
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.forename: Ming
authors.initials: M
authors.lastname: Lu