Optical in Situ Study of InP(100) Surface Chemistry: Dissociative Adsorption of Water and Oxygen

详细信息    查看全文

• 作者：Matthias M. May ; Hans-Joachim Lewerenz ; Thomas Hannappel
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 21, 2014
• 年：2014
• 卷：118
• 期：33
• 页码：19032-19041
• 全文大小：599K
• ISSN：1932-7455

文摘

Semiconductors designated for solar water-splitting need to be simultaneously stable and efficient in the charge transfer over the interface to the aqueous electrolyte. Although InP(100) has been employed as photocathode for several decades, no experimental data on its initial interaction with water is available. We study reaction mechanisms of well-defined surfaces with water and oxygen employing photoelectron and in situ reflection anisotropy spectroscopy. Our findings show that reaction path and stability differ significantly with atomic surface reconstruction. While the mixed-dimer In-rich surface exhibits dissociative water adsorption featuring In鈥揙鈥揚 rather than unfavorable In鈥揙鈥揑n bond topologies, the H-terminated, P-rich surface reconstruction is irreversibly removed. Oxygen exposure attacks the In-rich surface more efficiently and additionally modifies, unlike water exposure, bulk-related optical transitions. Hydroxyl is not observed, which suggests a dehydrogenation of adsorbed species already at ambient temperature. Our findings may benefit the design of InP(100) surfaces for photoelectrochemical water splitting.