Conversion of ALD CuO Thin Films into Transparent Conductive p‐Type CuI Thin Films. Issue 3 (4th December 2022)

• Record Type: Journal Article
• Authors: Weiß, Alexander; Goldmann, Jacqueline; Kettunen, Sakari; Popov, Georgi; Iivonen, Tomi; Mattinen, Miika; Jalkanen, Pasi; Hatanpää, Timo; Leskelä, Markku; Ritala, Mikko; Kemell, Marianna
• Is Part Of: Advanced materials interfaces. Volume 10:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-04
• Subjects: atomic layer deposition -- copper(I) iodide -- hole transport layer -- perovskite solar cell -- transparent p‐type semiconductor; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202201860
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Copper iodide (CuI) is a high‐performance p‐type transparent semiconductor that can be used in numerous applications, such as transistors, diodes, and solar cells. However, the lack of conformal and scalable methods to deposit CuI thin films limits its establishment in applications that involve complex‐shaped and/or large substrate areas. In this work, atomic layer deposition (ALD) is employed to enable scalable and conformal thin film deposition. A two‐step approach relying on ALD of CuO and its subsequent conversion to CuI via exposure to HI vapor at room temperature is demonstrated. The resulting CuI films are phase‐pure, uniform, and of high purity. Furthermore, CuI films on several substrates such as Si, amorphous Al2 O3, n‐type TiO2, and γ‐CsPbI3 perovskite are prepared. With the resulting n‐TiO2 /p‐CuI structure, the easy and straightforward fabrication of a diode structure as a proof‐of‐concept device is demonstrated. Moreover, the successful deposition of CuI on γ‐CsPbI3 proves the compatibility of the process for using CuI as the hole transport layer in perovskite solar cell applications in the nip‐configuration. It is believed that the ALD‐based approach described in this work will offer a viable alternative for depositing transparent conductive p‐type CuI thin films in applications that involve complex high aspect ratio structures and large substrate areas. Abstract : Copper iodide (CuI) is a high‐performance p‐type transparent semiconductor. Yet, CuI lacks processes for scalable and conformal thin film deposition. In this work, this issue is tackled by a novel approach relying on atomic layer deposition of CuO and its conversion into CuI at room temperature, yielding phase‐pure, uniform, and high purity CuI thin films.