Epitaxial Electrodeposition of Optically Transparent Hole-Conducting CuI on N-Si(111)


The expansion of future optoelectronic materials into transparent flexible electronics, perovskite, organic, and tandem photovoltaics depends on the development of high-performance p-type materials with optical transparency. We introduce the epitaxial growth of γ-CuI, a wide band gap p-type semiconductor with the zinc blende structure, on single crystalline Si(111) using a simple, cost-effective, room-temperature electrochemical method. The deposited epitaxial film grows with a high degree of in-plane and out-of-plane order, templated by the Si(111) substrate. A deposition mechanism is proposed, in which epitaxial CuI seed crystals are nucleated on the freshly etched n-Si(111) surface, followed by the simultaneous oxidation of Si to form a thin layer of SiOx and the lateral overgrowth of the CuI seeds into a continuous film. The rectifying p-CuI/SiOx/n-Si heterojunction diode shows an ideality factor of 1.5, a built-in voltage of 0.67 V, and a barrier height of 0.91 eV. The epitaxial CuI film has been epitaxially lifted off by chemical etching to produce textured CuI foils with an out-of-plane and in-plane order that mimics that of single crystals.




This material is based on work supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under grant no. DE-FG02-08ER46518.

International Standard Serial Number (ISSN)

0897-4756; 1520-5002

Document Type

Article - Journal

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Publication Date

11 May 2021