Low-epsilon titanium oxide antenna infrared photodetector

Area of Science:

• Nanotechnology
• Materials Science
• Optoelectronics

Background:

• Optical antennas offer high photoelectric efficiency but face fabrication challenges due to their small size.
• Noble metal optical antennas with negative permittivity are difficult to fabricate accurately.

Purpose of the Study:

• To develop a method for fabricating small-sized optical antennas with high precision.
• To create a novel optical antenna for infrared detection and optical-to-direct current conversion.

Main Methods:

• Fabrication of low-permittivity titanium oxide (TiO_x) films by controlling oxygen content.
• Construction of a TiO_x/Au bow-tie antenna coupled with a TiO_x/TiO₂/Au tunneling diode.
• In situ oxidation of TiO_x covered by an Au film.

Main Results:

• A 3.7 μm TiO_x/Au bow-tie antenna was successfully built.
• The rectifying antenna demonstrated the ability to convert optical waves to direct current around 900 nm.
• The low-permittivity TiO_x facilitated displacement current flow, overcoming fabrication limits.

Conclusions:

• This work presents a new approach to overcome the size limitations of noble metal optical antennas.
• The developed TiO_x-based antenna shows potential for advanced infrared detection and energy conversion applications.