title: Interface engineering by piezoelectric potential in ZnO-based photoelectrochemical anode.
abstract: Through a process of photoelectrochemical (PEC) water splitting, we demonstrated an effective strategy for engineering the barrier height of a heterogeneous semiconductor interface by piezoelectric polarization, known as the piezotronic effect. A consistent enhancement or reduction of photocurrent was observed when tensile or compressive strains were applied to the ZnO anode, respectively. The photocurrent variation is attributed to a changed barrier height at the ZnO/ITO interface, which is a result of the remnant piezoelectric potential across the interface due to a nonideal free charge distribution in the ITO electrode. In our system, ∼1.5 mV barrier height change per 0.1% applied strain was identified, and 0.21% tensile strain yielded a ∼10% improvement of the maximum PEC efficiency. The remnant piezopotential is dictated by the screening length of the materials in contact with piezoelectric component. The difference between this time-independent remnant piezopotential effect and time-dependent piezoelectric effect is also studied in details.
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Starr
authors.forename: Hua
authors.initials: H
authors.lastname: Xiang
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hara
authors.forename: Marc A
authors.initials: MA
authors.lastname: Anderson
authors.forename: Jung-Hun
authors.initials: JH
authors.lastname: Seo
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Ma
authors.forename: Xudong
authors.initials: X
authors.lastname: Wang