Quantifying the Coupled Role of Mie Resonance Order and Geometry in Hot-Electron Photodetection
- 1Engineering Research Center of Advanced Functional Materials and Intelligent Sensing & School of Physical Science and Technology, Guangxi Normal University, Guilin 541004, China
- 2School of Physical Science and Technology, Tiangong University, Tianjin 300387, China
Abstract
Hot-electron photodetectors (HE-PDs) convert photon-excited hot carriers into photocurrents. Although optical resonances often have multiple orders, how the resonance order influences HE-PD performance remains unclear. Using a coaxial Ag–TiO2 nanowire as a model system, we investigate the role of Mie resonance order |m| in the Ag–TiO2 junction. For coaxial nanowires, the Mie resonance order and the device geometry are intrinsically coupled because higher-order Mie resonance necessarily requires a larger TiO2 core. By fixing the Ag shell thickness at 8 nm and varying only the TiO2 core radius, we excite pure Mie resonances from the first to the eighth order at an identical wavelength of 900 nm. We find that |m| directly determines the spatial distribution of hot-electron generation and indirectly leads to increasing separation between the generation site and the metal–semiconductor interface with a rise in |m|. Moreover, the internal quantum efficiency of the designed HE-PD decreases under the combined effect of the device size and |m| variation, which is attributed to the increased hot-electron travel distance in the coaxial structure and the reduced transport probability. In contrast, external quantum efficiency, which convolutes photon absorption with internal quantum efficiency, increases with |m| and reaches its maximum at the sixth order because of the highest normalized absorption cross section at |m| = 6. In addition, both the absorption and external quantum efficiency spectra narrow, and their linewidths decrease as the resonance order increases. Overall, our study highlights the critical role of |m| intrinsically coupled with device geometry in HE PD performance, deepening our understanding of resonance order effects in hot-electron devices.
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BibTeX
@article{long2026quantifying,
title = {{Quantifying the Coupled Role of Mie Resonance Order and Geometry in Hot-Electron Photodetection}},
author = {Qiuyi Long and Longbo Jiao and Jia Hao and Lili Xie and Yizhi Wu and Weijia Shao and Qingjia Zhou},
journal = {Nanomaterials},
year = {2026},
month = oct,
doi = {10.3390/nano16201312},
url = {https://www.mdpi.com/2079-4991/16/20/1312},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Quantifying the Coupled Role of Mie Resonance Order and Geometry in Hot-Electron Photodetection
AU - Qiuyi Long
AU - Longbo Jiao
AU - Jia Hao
AU - Lili Xie
AU - Yizhi Wu
AU - Weijia Shao
AU - Qingjia Zhou
PY - 2026
DA - 2026/10/01
JO - Nanomaterials
DO - 10.3390/nano16201312
UR - https://www.mdpi.com/2079-4991/16/20/1312
AB - Hot-electron photodetectors (HE-PDs) convert photon-excited hot carriers into photocurrents. Although optical resonances often have multiple orders, how the resonance order influences HE-PD performance remains unclear. Using a coaxial Ag–TiO2 nanowire as a model system, we investigate the role of Mie resonance order |m| in the Ag–TiO2 junction. For coaxial nanowires, the Mie resonance order and the device geometry are intrinsically coupled because higher-order Mie resonance necessarily requires a larger TiO2 core. By fixing the Ag shell thickness at 8 nm and varying only the TiO2 core radius, we excite pure Mie resonances from the first to the eighth order at an identical wavelength of 900 nm. We find that |m| directly determines the spatial distribution of hot-electron generation and indirectly leads to increasing separation between the generation site and the metal–semiconductor interface with a rise in |m|. Moreover, the internal quantum efficiency of the designed HE-PD decreases under the combined effect of the device size and |m| variation, which is attributed to the increased hot-electron travel distance in the coaxial structure and the reduced transport probability. In contrast, external quantum efficiency, which convolutes photon absorption with internal quantum efficiency, increases with |m| and reaches its maximum at the sixth order because of the highest normalized absorption cross section at |m| = 6. In addition, both the absorption and external quantum efficiency spectra narrow, and their linewidths decrease as the resonance order increases. Overall, our study highlights the critical role of |m| intrinsically coupled with device geometry in HE PD performance, deepening our understanding of resonance order effects in hot-electron devices.
SN - 2079-4991
ER -