Atomic Layer Deposition of PbS Thin Films at Low Temperatures

Georgi Popov (Corresponding Author), Goran Bačić, Miika Mattinen, Toni Manner, Hannu Lindström, Heli Seppänen, Sami Suihkonen, Marko Vehkamäki, Marianna Kemell, Pasi Jalkanen, Kenichiro Mizohata, Jyrki Räisänen, Markku Leskelä, Hanna Maarit Koivula, Seán T. Barry, Mikko Ritala (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Atomic layer deposition (ALD) is a viable method for depositing functional, passivating, and encapsulating layers on top of halide perovskites. Studies in that area have only focused on metal oxides, despite a great number of materials that can be made with ALD. This work demonstrates that, in addition to oxides, other ALD processes can be compatible with the perovskites. We describe two new ALD processes for lead sulfide. These processes operate at low deposition temperatures (45-155 °C) that have been inaccessible to previous ALD PbS processes. Our processes rely on volatile and reactive lead precursors Pb(dbda) (dbda = rac-N2,N3-di-tert-butylbutane-2,3-diamide) and Pb(btsa)2 (btsa = bis(trimethylsilyl)amide) as well as H2S. These precursors produce high quality PbS thin films that are uniform, crystalline, and pure. The films exhibit p-type conductivity and good mobilities of 10-70 cm2 V-1 s-1. Low deposition temperatures enable direct ALD of PbS onto a halide perovskite CH3NH3PbI3 (MAPI) without its decomposition. The stability of MAPI in ambient air is greatly improved by capping with ALD PbS. More generally, these new processes offer valuable alternatives for PbS-based devices, and we hope that this study will inspire more studies on ALD of non-oxides on halide perovskites.

Original languageEnglish
Pages (from-to)8216−8228
Number of pages13
JournalChemistry of Materials
Volume32
Issue number19
DOIs
Publication statusPublished - 13 Oct 2020
MoE publication typeA1 Journal article-refereed

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