Photonic-plasmonic hot-electron-based photodetection with diffracted-order-resolved leaky plasmonic mechanisms

Area of Science:

• Plasmonics
• Optoelectronics
• Materials Science

Background:

• Hot-carrier photodetectors utilizing plasmonic effects are widely researched.
• Achieving high external quantum efficiency (EQE) and small active areas in visible-frequency photodetectors remains challenging.

Purpose of the Study:

• To propose, analyze, and experimentally demonstrate a novel hot-electron-based, non-trench-type photodetector.
• To investigate the optical absorption mechanism in a thin aluminum film using leaky plasmonic modes.
• To achieve high performance metrics for practical low-voltage photodetection.

Main Methods:

• Diffracted-order-resolved analytical analysis and numerical computations to understand optical absorption.
• Experimental demonstration of a novel photodetector design.
• Current-voltage measurements to estimate the RC time constant.

Main Results:

• The design utilizes pure photoexcitation in a thin aluminum film and leaky plasmonic modes.
• Leaky surface plasmon resonance and quasibound supermodes significantly enhance absorptance in the aluminum film.
• At 638.9 nm and -0.9951 V bias, key performance metrics include responsivity (298.1444 μA/mW/mm²), detectivity (4.3809 × 10⁹ cm Hz¹/² /W), and EQE (2.6878%).
• The active area was 4.6457 × 10⁻² mm².
• The RC time constant was estimated at 1.673 μs.

Conclusions:

• The developed photodetector demonstrates high performance, comparable to existing devices at similar wavelengths and biases.
• The physical insights gained can facilitate the practical application of low-voltage, metal-based photodetectors.
• The innovative design offers a promising direction for future optoelectronic device development.