Enhanced thermoelectricity at the ultra-thin film limit

Abstract

At the ultra-thin film limit, quantum confinement strongly improves thermoelectric figure of merit in materials such as Sb${}_2$Te${}_3$ and Bi${}_2$Te${}_3$. These high quality films have only been realized using well controlled techniques such as molecular beam epitaxy. We report a two fold increase in the Seebeck coefficient for both p-type Sb${}_2$Te${}_3$ and n-type Bi${}_2$Te${}_3$ using thermal co-evaporation, an affordable approach. At the thick film limit greater than 100 nm, their Seebeck coefficients are around 100 $\mu V/K$, similar to results obtained in other work. When the films are thinner than 50 nm, the Seebeck coefficient increases to about 500 $\mu V/K$. With a total Seebeck coefficient $\sim$ 1 mV/K and an estimate ZT $\sim$ 2, this pair of materials is the first step to a practical micro-cooler at room temperature.

arXiv comment4 pages, 4 figures

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Cited by in corpus (1)

• An in-situ thermoelectric measurement apparatus inside a thermal-evaporator