Thermoelectric Devices Incorporating Photonic Resonance Segments

Abstract

Thermoelectric devices integrated with optical resonance absorbers are demonstrated. We design the absorbers with rigorous numerical methods and fashion experimental prototypes by thin-film deposition, patterning, and etching. A $\sim 2.5$ - $\mu \text{m}$ -thick p-type heavily doped polysilicon film on a $\sim 2$ - $\mu \text{m}$ layer of thermally grown SiO2 enables guided-mode resonance. The SiO2 layer additionally serves to thermally insulate the polysilicon layer from the Si substrate. A grating layer is etched into the polysilicon film to form the absorber. Thus, the polysilicon film works as functional material for both the absorber and the thermoelectric converter itself. Numerical simulations show that the resonance segment enhances absorption by $\sim 30$ % in the visible spectral range and by $\sim 40$ % in the infrared (IR) range relative to unpatterned devices. Moreover, the experimental results demonstrate significantly increased electrical output over reference devices. These simple devices can be applied as compact voltage generators and IR sensors.