标题：Two-step vapor deposition of self-catalyzed large-size PbI2nanobelts for high-performance photodetectors
作者：Han, Mingming ;Sun, Jiamin ;Bian, Luozhen ;Wang, Zhou ;Zhang, Lei ;Yin, Yanxue ;Gao, Zhaofeng ;Li, Fulin ;Xin, Qian ;He, Longbin ;Han, Ning ;Song, Aim 更多 作者机构：[Han, Mingming ;Sun, Jiamin ;Bian, Luozhen ;Yin, Yanxue ;Gao, Zhaofeng ;Li, Fulin ;Xin, Qian ;Song, Aimin ;Yang, Zai-Xing ] Center of Nanoelectronics, 更多
来源：Journal of Materials Chemistry C
摘要：The grown lead iodide (PbI2) is usually a two-dimensional sheet with a finite size which necessitates sophisticated device metallization and the growth of quasi one-dimensional materials is still challenging. In this work, large-size (length > 100 μm), single-crystalline and high-density PbI2nanobelts are successfully synthesized by manipulating the microenvironment in a two-step vapor deposition process at a slow heating rate of ∼18 °C min-1. Firstly, PbI2nanosheet seeds are grown by physical vapor deposition, and then PbI2nanobelts are synthesized by a self-catalyzed vapor-liquid-solid growth mechanism, which is verified by the Pb nanoparticles on the nanobelt tips. Photoluminescence and ultraviolet-visible spectra show the uniform high-quality crystallinity of the as-prepared large-size PbI2nanobelts with a bandgap of 2.36 eV. When configured into photodetectors with a shadow mask, the fabricated device exhibits a low dark current of 4 pA, an impressive ON/OFF current ratio of 103-104, a photoresponsivity of 13 mA W-1, and a fast response with the rise and decay time constants of 425 and 41 ms, respectively. All these performances are comparable to those of state-of-the-art layered PbI2nanostructure photodetectors, but the ease of synthesizing large-size PbI2nanobelts may have a useful impact on next-generation easily-fabricated high-performance optoelectronics.
© 2018 The Royal Society of Chemistry.