Mechanistic investigation on tuning the conductivity type of cuprous oxide (Cu2O) thin films via deposition potential. (26th July 2018)

• Record Type: Journal Article
• Authors: Han, Juan; Chang, Jing; Wei, Rong; Ning, Xiaohui; Li, Jian; Li, Zuoxi; Guo, Huilin; Yang, Ying
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 30(2018)
• Page Start: 13764
• Page End: 13777
• Publication Date: 2018-07-26
• Subjects: Conductivity type -- Cuprous oxide (Cu2O) -- Thin film -- Semiconductor -- Photoelectrochemistry; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.02.121
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The conductivity type of cuprous oxide (Cu2 O) thin films is tuned by controlling the deposition potential of an electrochemical process in an acid cupric acetate solution containing sodium dodecyl sulfate. The morphology and chemical composition of the deposited Cu2 O films are studied by SEM, XRD and XPS. The change of the conductivity type of Cu2 O films is further studied through zero-bias photocurrent and Mott-Schottky measurements. The results indicate that the Cu2 O films behave as n-type semiconductors when the overpotentials are low (potentials higher than −0.05 V) and p-type semiconductors when the overpotentials are high (potentials lower than −0.10 V). The transformation of conductivity from n-type to p-type comes from the competition reactions between forming Cu2 O and forming metallic Cu from Cu 2+ . When the potential is lower than −0.10 V, most of Cu 2+ are consumed by the growth of metallic Cu at the film/solution interface, so that the Cu 2+ provided to grow Cu2 O film are insufficient and copper vacancies form in the film, leading to the p-type conductivity. Highlights: The conductivity type of Cu2 O films is tuned by controlling the potential. The semiconducting performances of Cu2 O films are facilely tuned. The donor densities of n-Cu2 O films decreases with decreasing potential. The acceptor densities of p-Cu2 O films increases with decreasing potential.