A thermoelectric generator using porous Si thermal isolation

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Thermoelectric generators (TEGs) offer a promising avenue for waste heat energy conversion.
• Efficient thermal isolation is crucial for maximizing TEG performance.
• Porous silicon (PS) has emerged as a viable material for thermal management in microelectronic devices.

Purpose of the Study:

• To develop and characterize a novel thermoelectric generator (TEG) employing porous silicon for enhanced thermal isolation.
• To investigate the impact of porous silicon layer properties on TEG performance.
• To demonstrate the feasibility of integrating TEG fabrication with standard silicon processing.

Main Methods:

• Fabrication of a TEG utilizing a thick porous silicon layer for thermal isolation between hot and cold thermocouple junctions.
• Thermocouples were constructed from p-doped polycrystalline silicon/aluminum.
• Characterization of the TEG's output power under a macroscopic temperature differential.

Main Results:

• A TEG incorporating a 50 μm thick mesoporous silicon layer (60% porosity) achieved an output power density of 0.39 μW/cm2.
• The output power was found to be dependent on porous silicon layer thickness, porosity, structure, and morphology.
• The fabrication process is compatible with batch silicon processing.

Conclusions:

• Porous silicon is an effective material for thermal isolation in thermoelectric generators.
• The developed TEG design demonstrates potential for efficient energy harvesting applications.
• Further optimization of porous silicon properties can lead to improved thermoelectric performance.