title: Semiconductor interfacial carrier dynamics via photoinduced electric fields.
abstract: Solar photoconversion in semiconductors is driven by charge separation at the interface of the semiconductor and contacting layers. Here we demonstrate that time-resolved photoinduced reflectance from a semiconductor captures interfacial carrier dynamics. We applied this transient photoreflectance method to study charge transfer at p-type gallium-indium phosphide (p-GaInP2) interfaces critically important to solar-driven water splitting. We monitored the formation and decay of transient electric fields that form upon photoexcitation within bare p-GaInP2, p-GaInP2/platinum (Pt), and p-GaInP2/amorphous titania (TiO2) interfaces. The data show that a field at both the p-GaInP2/Pt and p-GaInP2/TiO2 interfaces drives charge separation. Additionally, the charge recombination rate at the p-GaInP2/TiO2 interface is greatly reduced owing to its p-n nature, compared with the Schottky nature of the p-GaInP2/Pt interface.
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. ye.yang@nrel.gov matt.beard@nrel.gov.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Gu
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. Material Science and Engineering Program, University of Colorado, Boulder, CO, 80309, USA.
authors.forename: James L
authors.initials: JL
authors.lastname: Young
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA.
authors.forename: Elisa M
authors.initials: EM
authors.lastname: Miller
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Turner
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA.
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Neale
authors.affiliation: National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. ye.yang@nrel.gov matt.beard@nrel.gov.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Beard