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arXiv · 1810.04238

Ultrafast Studies of Hot-Hole Dynamics in Au/p-GaN Heterostructures

Giulia Tagliabue·Joseph S. DuChene·Mohamed Abdellah·Adela Habib·Yocefu Hattori·Kaibo Zheng·Sophie E. Canton·David J. Gosztola·Wen-Hui Cheng·Ravishankar Sundararaman·Jacinto Sa·Harry A. Atwater
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Abstract

Harvesting non-equilibrium hot carriers from photo-excited metal nanoparticles has enabled plasmon-driven photochemical transformations and tunable photodetection with resonant nanoantennas. Despite numerous studies on the ultrafast dynamics of hot electrons, to date, the temporal evolution of hot holes in metal-semiconductor heterostructures remains unknown. An improved understanding of the carrier dynamics in hot-hole-driven systems is needed to help expand the scope of hot-carrier optoelectronics beyond hot-electron-based devices. Here, using ultrafast transient absorption spectroscopy, we show that plasmon-induced hot-hole injection from gold (Au) nanoparticles into the valence band of p-type gallium nitride (p-GaN) occurs within 200 fs, placing hot-hole transfer on a similar timescale as hot-electron transfer. We further observed that the removal of hot holes from below the Au Fermi level exerts a discernible influence on the thermalization of hot electrons above it, reducing the peak electronic temperature and decreasing the electron-phonon coupling time relative to Au samples without a pathway for hot-hole collection. First principles calculations corroborate these experimental observations, suggesting that hot-hole injection modifies the relaxation dynamics of hot electrons in Au nanoparticles through ultrafast modulation of the d-band electronic structure. Taken together, these ultrafast studies substantially advance our understanding of the temporal evolution of hot holes in metal-semiconductor heterostructures and suggest new strategies for manipulating and controlling the energy distributions of hot carriers on ultrafast timescales.

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Giulia Tagliabue, Joseph S. DuChene, Mohamed Abdellah, Adela Habib, Yocefu Hattori, Kaibo Zheng, Sophie E. Canton, David J. Gosztola, Wen-Hui Cheng, Ravishankar Sundararaman, Jacinto Sa, Harry A. Atwater. 2018-10-09. Ultrafast Studies of Hot-Hole Dynamics in Au/p-GaN Heterostructures. https://doi.org/10.1038/s41563-020-0737-1

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