title: Laser-induced greenish-blue photoluminescence of mesoporous silicon nanowires.
abstract: Solid silicon nanowires and their luminescent properties have been widely studied, but lesser is known about the optical properties of mesoporous silicon nanowires (mp-SiNWs). In this work, we present a facile method to generate greenish-blue photoluminescence (GB-PL) by fast scanning a focused green laser beam (wavelength of 532 nm) on a close-packed array of mp-SiNWs to carry out photo-induced chemical modification. The threshold of laser power is 5 mW to excite the GB-PL, whose intensity increases with laser power in the range of 5-105 mW. The quenching of GB-PL comes to occur beyond 105 mW. The in-vacuum annealing effectively excites the GB-PL in the pristine mp-SiNWs and enhances the GB-PL of the laser-modified mp-SiNWs. A complex model of the laser-induced surface modification is proposed to account for the laser-power and post-annealing effect. Moreover, the fast scanning of focused laser beam enables us to locally tailor mp-SiNWs en route to a wide variety of micropatterns with different optical functionality, and we demonstrate the feasibility in the application of creating hidden images.
authors.affiliation: 1] Hwa Chong Institution, 661 Bukit Timah Rd., Singapore 269734, Singapore [2].
authors.forename: Yan-Ru
authors.initials: YR
authors.lastname: Choi
authors.affiliation: 1] Department of Physics, 2 Science Drive 3, National University of Singapore (NUS), Singapore 117542, Singapore [2].
authors.forename: Minrui
authors.initials: M
authors.lastname: Zheng
authors.affiliation: 1] Department of Physics, Institute of Advanced Materials, Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University (HKBU), Kowloon Tong, Hong Kong SAR, P. R. China [2].
authors.forename: Fan
authors.initials: F
authors.lastname: Bai
authors.affiliation: Department of Physics, Institute of Advanced Materials, Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University (HKBU), Kowloon Tong, Hong Kong SAR, P. R. China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore (NUS), Singapore 117542, Singapore.
authors.forename: Eng-Soon
authors.initials: ES
authors.lastname: Tok
authors.affiliation: 1] Department of Physics, Institute of Advanced Materials, Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University (HKBU), Kowloon Tong, Hong Kong SAR, P. R. China [2] HKBU Institute of Research and Continuing Education, A211, Virtual University Park Building, South Area Hi-Tech Industrial Park, Shenzhen, Guangdong Province, P. R. China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore (NUS), Singapore 117542, Singapore.
authors.forename: Chorng-Haur
authors.initials: CH
authors.lastname: Sow