Structural and Photoelectrochemical Properties of GaP Nanowires Annealed in NH3

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• 作者：Wen Wen ; Azhar I. Carim ; Sean M. Collins ; Michelle J. Price ; Sabrina L. Peczonczyk ; Stephen Maldonado
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：November 17, 2011
• 年：2011
• 卷：115
• 期：45
• 页码：22652-22661
• 全文大小：1067K
• 年卷期：v.115,no.45(November 17, 2011)
• ISSN：1932-7455

文摘

Nitrogen alloyed gallium phosphide (GaP_1鈥?i>xN_x) nanowires have been prepared by annealing gallium phosphide (GaP) nanowires in flowing NH₃(g) at 750 掳C. X-ray diffraction patterns and electron microscopy showed that changes in the annealing conditions afforded controlled alloying of N without effecting a complete conversion to gallium nitride (GaN). Raman measurements on nanowire films and individual nanowires highlighted intense new signatures, consistent with symmetry reduction from N incorporation in the zincblende lattice. The resultant optical properties and photoresponse of the GaP_1鈥?i>xN_x nanowire films were investigated by wavelength-dependent diffuse reflectance and photoelectrochemical measurements, respectively. Diffuse reflectance measurements showed progressively lower reflectivity of visible light for nanowire films annealed in increasingly higher levels of NH₃(g), indicating an increased light absorption. Corresponding photoelectrochemical measurements of the GaP_1鈥?i>xN_x nanowires revealed an increased quantum efficiency, relative to GaP, for energy conversion of light with wavelengths longer than 545 nm. The presented data set thus identifies a methodology for improving the solar energy conversion properties of GaP nanowire film photoelectrodes for visible light.