Plasmons Enhancing Sub-Bandgap Photoconductivity in TiO<sub>2</sub> Nanoparticles Film
Mohammed A. Ibrahem, E. Verrelli, Ali M. Adawi, Jean‐Sebastien G. Bouillard, Mary O’Neill
Abstract
High Resolution Image Download MS PowerPoint Slide The coupling between sub-bandgap defect states and surface plasmon resonances in Au nanoparticles and its effects on the photoconductivity performance of TiO 2 are investigated in both the ultraviolet (UV) and visible spectrum. Incorporating a 2 nm gold nanoparticle layer in the photodetector device architecture creates additional trapping pathways, resulting in a faster current decay under UV illumination and a significant enhancement in the visible photocurrent of TiO 2, with an 8-fold enhancement of the defects-related photocurrent. We show that hot electron injection (HEI) and plasmonic resonance energy transfer (PRET) jointly contribute to the observed photoconductivity enhancement. In addition to shedding light on the below-band-edge photoconductivity of TiO 2, our work provides insight into new methods to probe and examine the surface defects of metal oxide semiconductors using plasmonic resonances.