Comparison of GaP nanowires grown from Au and Sn vapor-liquid-solid catalysts as photoelectrode materials

• Published in: Journal of crystal growth Vol. 482; no. C; pp. 36 - 43
• Main Authors: Lee, Sudarat, Wen, Wen, Cheek, Quintin, Maldonado, Stephen
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2018; Elsevier BV; Elsevier
• Subjects: A1. Crystal structure; A1. Defects; B1. Gallium compounds; B2. Semiconducting III–V materials; Catalysis; Catalysts; Crystallography; Electrodes; Electrolytes; Electrolytic cells; Gallium phosphides; Gold; Materials Science; Nanoparticles; Nanowires; Nonaqueous electrolytes; Physics; Raman spectra; Sublimation; Substrates; Tin; White light; B1. Gallium compounds; B2. Semiconducting III–V materials; A1. Crystal structure; A1. Defects
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2017.10.021

•Sn nanoparticles can readily act as a VLS growth catalyst for GaP nanowire deposition.•Sn nanoparticles could be more easily removed by acid etching.•Au- and Sn-seeded GaP nanowires were non-degenerate n-type and degenerate n-type, respectively. Gallium phosphide (GaP) nanowire film electrodes have been prepared via solid sublimation of GaP powder using both gold (Au) and tin (Sn) nanoparticles as the vapor-liquid-solid (VLS) catalysts on Si(1 1 1) and GaP(1 1 1)B substrates. The resultant GaP nanowires are compared and contrasted in terms of structures and photoactivity in photoelectrochemical half cells. Raman spectra implicated a difference in the surface condition of the two types of nanowires. Complete wet etching removal of metallic VLS catalysts from the as-prepared GaP nanowires was possible with Sn catalysts but not with Au catalysts. The photoresponses of both Sn- and Au-seeded GaP nanowire films were collected and examined under 100 mW cm−2 white light illumination. Au-seeded nanowire films exhibited strong n-type characteristics when measured in nonaqueous electrolyte with ferrocene/ferricenium as the redox species while Sn-seeded nanowires showed behavior consistent with degenerate n-type doping.