Silicon based mid-IR super absorber using hyperbolic metamaterial.

Area of Science:

• Photonics and Metamaterials
• Nanotechnology
• Energy Harvesting

Background:

• Perfect absorbers are crucial for energy harvesting but often suffer from bulkiness and instability.
• Existing absorbers lack CMOS compatibility, hindering on-chip integration.
• There is a need for stable, compact, and efficient absorbers for advanced applications.

Purpose of the Study:

• To theoretically demonstrate a Silicon (Si)-based mid-infrared super absorber.
• To achieve high absorption with CMOS compatibility for on-chip applications.
• To explore tunable and broadband absorption capabilities.

Main Methods:

• Utilized multilayered N-doped Si/Si hyperbolic metamaterial (HMM) integrated with sub-hole Si grating.
• Investigated tunable absorption by varying grating parameters (4.5 µm to 11 µm).
• Proposed two grating designs for broadband absorption using variable hole heights and diameters.

Main Results:

• Achieved a maximum absorption (A) of 0.948 with the proposed Si-based structure.
• Demonstrated tunable absorption peaks from 4.5 µm to 11 µm.
• Obtained broadband absorption with A ranging from 0.83 to 0.97, and a maximum of 0.97 for specific designs.

Conclusions:

• The proposed all-Si absorber is CMOS compatible and offers tunable and broadband absorption.
• The structure exhibits omnidirectional absorption characteristics.
• This efficient Si-based absorber is a promising candidate for thermal harvesting applications.