Synthesis, Characterization, and Variable Range Hopping Transport of Pyrite (FeS2) Nanorods, Nanobelts, and Nanoplates

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• 作者：Miguel Cab谩n-Acevedo ; Dong Liang ; Kit S. Chew ; John P. DeGrave ; Nicholas S. Kaiser ; Song Jin
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：7
• 期：2
• 页码：1731-1739
• 全文大小：535K
• 年卷期：v.7,no.2(February 26, 2013)
• ISSN：1936-086X

文摘

We report the growth, structural, and electrical characterization of single-crystalline iron pyrite (FeS₂) nanorods, nanobelts, and nanoplates synthesized via sulfidation reaction with iron dichloride (FeCl₂) and iron dibromide (FeBr₂). The as-synthesized products were confirmed to be single-crystal phase pure cubic iron pyrite using powder X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. An intermediate reaction temperature of 425 掳C or a high sulfur vapor pressure under high temperatures was found to be critical for the formation of phase pure pyrite. Field effect transport measurements showed that these pyrite nanostructures appear to behave as a moderately p-doped semiconductor with an average resistivity of 2.19 卤 1.21 惟路cm, an improved hole mobility of 0.2 cm² V^鈥? s^鈥?, and a lower carrier concentration on the order of 10¹⁸鈥?0¹⁹ cm^鈥? compared with previous reported pyrite nanowires. Temperature-dependent electrical transport measurements reveal Mott variable range hopping transport in the temperature range 40鈥?20 K and transport via thermal activation of carriers with an activation energy of 100 meV above room temperature (300鈥?00 K). Most importantly, the transport properties of the pyrite nanodevices do not change if highly pure (99.999%) precursors are utilized, suggesting that the electrical transport is dominated by intrinsic defects in pyrite. These single-crystal pyrite nanostructures are nice platforms to further study the carrier conduction mechanisms, semiconductor defect physics, and surface properties in depth, toward improving the physical properties of pyrite for efficient solar energy conversion.

Keywords:

iron pyrite; nanostructure; solar energy conversion; semiconductor transport; photovoltaics; photoelectrochemistry