(Invited) Chemical Stability and Electronic Behavior of Atomic Layer Deposited Metal Oxide Thin Films. (13th April 2015)

• Record Type: Journal Article
• Authors: Strandwitz, Nicholas C; Bao, Bo; Correa, Gabriela Calinao
• Is Part Of: ECS transactions. Volume 66:Number 6(2015)
• Page Start: 77
• Page End: 81
• Publication Date: 2015-04-13
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/06606.0077ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : Modification of semiconductor surfaces via the growth of metal oxide overlayers, particularly by atomic layer deposition (ALD), has become a topic of recent interest for surface passivation and chemical protection in semiconductor/liquid junctions. For example, in photoelectrochemical (PEC) water splitting, semiconductor surfaces typically must be protected with insulating or conducting layers that are stable in the electrochemical environment. Although thermodynamic stability of a solid phase in various environments can be readily assessed, complex phenomena such as film hydration and dynamic dissolution/precipitation can occur, impacting the efficacy of thin protective ALD films. We have examined the stability of the two of the most common ALD materials, alumina and titania, in a variety of environments. Film thickness was monitored after immersion in various liquid media. Our results indicate an increase in stability of the ALD films after post-deposition thermal treatment. Further, for alumina films in pure water, a restructuring occurs changing film density, thickness, and morphology. These results provide important guidelines for the applicability of ALD oxides as protective/passivating films on semiconductor electrodes for applications in sensing and photoelectrochemical water splitting.