Synthesis of Light-Absorbing ZnSnP2 Semiconductor Nanowires

The conjecture of ZnSnP₂ semiconductor nanowires as promising inexpensive solar absorber and the nanowire preparation method was discussed in this presentation. Single-phase crystalline ZnSnP₂ nanowires have been prepared via simple chemical-vapor-deposition (CVD) of Zn and SnP₃ powder in a custom-built tube furnace reactor, allowing the vapors to react with thermally evaporated Sn islands on 40 mm² Si(111) substrate. Powder X-ray diffraction data and Raman scattering of the nanowire films, along with single-nanowire analysis using high-resolution transmission electron microscope (HRTEM) indicate that the as-prepared ZnSnP₂ nanowires possess single-crystalline sphalerite structure, as opposed to the antisite defect-free chalcopyrite structure. Nonetheless, the nanowires show homogenous elemental distribution of Zn, Sn, and P, with chemical composition close to the 1:1:2 stoichiometric ratio. Photoelectrochemical measurements in aqueous electrolyte show the as-prepared ZnSnP₂ nanowires exhibit stable cathodic photoresponse under white light illumination. Tapered nanowires that lead to formation of Zn₃P₂ nanowires dominate at extended growth duration, implying the Sn islands serve both as the vapor-liquid-solid (VLS) growth seed and sole contributor of Sn. Approaches to minimize consumption of Sn will be presented to ensure production of long nanowire with consistent diameter. This study presents a benign and straightforward approach to prepare single-phase Zn-IV-P₂ nanowires suitable for energy conversion applications.