title: Catalytically solid-phase self-organization of nanoporous SnS with optical depolarizability.
abstract: The catalytic solid-phase synthesis of self-organized nanoporous tin sulfide (SnS) with enhanced absorption, manipulative transmittance and depolarization features is demonstrated. Using an ultralow radio-frequency (RF) sputtering power, the variation of the orientation angle between the anodized aluminum oxide (AAO) membrane and the axis of the sputtered ion beam detunes the catalytically synthesized SnS from nanorod to nanoporous morphology, along the sidewall of the AAO membrane. The ultraslow catalytic sputtering synthesis on the AAO at the RF plasma power of 20 W and the orientation angle of 0° regulates the porosity and integrality of nanoporous SnS, with average pore diameter of 80-150 nm. When transferring from planar to nanoporous structure, the phase composition changes from SnS to SnS2-Sn2S3, and the optical bandgap shrinks from 1.43 to 1.16 eV, due to the preferred crystalline orientation, which also contributes to an ultralow reflectance of <1% at 200-500 nm when both the transmittance and the surface scattering remain at their maxima. The absorption coefficient is enhanced by nearly one order of magnitude with its minimum of >5 × 10(4) cm(-1) at the wavelength between 200 and 700 nm, due to the red-shifting of the absorption spectrum to at least 100 nm. The catalytically self-organized nanoporous SnS causes strong haze and beam divergence of 20°-30° by depolarized nonlinear scattering at the surface, which favors the solar energy conversion with reduced surface reflection and enhanced photon scattering under preserved transmittance.
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Chih-Hsien
authors: CH
authors: Cheng
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Yu-Chieh
authors: YC
authors: Chi
authors: Department of Photonics and Department of Physics, National Sun Yat-sen University, No. 70, Lien-Hai Rd., Kaohsiung 804, Taiwan.
authors: Chung-Lun
authors: CL
authors: Wu
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Chun-Jung
authors: CJ
authors: Lin
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Ling-Hsuan
authors: LH
authors: Tsai
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Jung-Hung
authors: JH
authors: Chang
authors: Department of Physics, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China.
authors: Mu Ku
authors: MK
authors: Chen
authors: Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan and Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
authors: Min-Hsiung
authors: MH
authors: Shih
authors: Department of Photonics and Department of Physics, National Sun Yat-sen University, No. 70, Lien-Hai Rd., Kaohsiung 804, Taiwan.
authors: Chao-Kuei
authors: CK
authors: Lee
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Chih-I
authors: CI
authors: Wu
authors: Department of Physics, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China and Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
authors: Din Ping
authors: DP
authors: Tsai
authors: Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan, Republic of China. grlin@ntu.edu.tw.
authors: Gong-Ru
authors: GR
authors: Lin