Germanium Metasurfaces with Lattice Kerker Effect in Near-Infrared Photodetectors

Area of Science:

• Photonics and optical communications
• Nanotechnology and metamaterials
• Semiconductor device physics

Background:

• Germanium (Ge) is a key material for optical detectors in O- and C-band communications.
• Metasurfaces offer novel ways to manipulate light-matter interactions.
• Lattice resonances in periodic nanostructures can enhance optical properties.

Purpose of the Study:

• To investigate 2D periodic Germanium metasurfaces for enhanced optical detection.
• To achieve narrowband absorption using the resonant lattice Kerker effect.
• To improve the performance of Germanium-based photodetectors.

Main Methods:

• Fabrication of 2D periodic Germanium metasurfaces with nanoantenna arrays.
• Excitation of optically induced electric dipole and magnetic dipole lattice resonances.
• Analysis of Mie resonances and their overlap with lattice resonances.
• Measurement of absorptance and photocurrent in fabricated devices.

Main Results:

• Demonstration of the resonant lattice Kerker effect by overlapping Mie and lattice resonances.
• Achieved narrowband absorption in the Germanium metasurfaces.
• Observed a 6-fold increase in absorptance for Ge nanoantenna arrays compared to unpatterned films.
• Reported an approximately 5-fold increase in photocurrent for Ge metasurface photodetectors.

Conclusions:

• 2D periodic Ge metasurfaces enable the resonant lattice Kerker effect for enhanced optical absorption.
• The demonstrated Ge metasurface photodetectors show significantly improved performance due to strong near-field interactions.
• This work highlights the potential of Ge metasurfaces for advanced optical communication applications.