Thermoelectric generator and solid-state battery for stand-alone microsystems

This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi 2 Te 3 ) and p-type antimony telluride (Sb 2 Te 3 ), which were deposited using co-evaporation. The measurements on selected samples of Bi 2 Te 3 and Sb 2 Te 3 thin films indicated a Seebeck coefficient in the range of 90–250 µV K −1 and an in-plane electrical resistivity in the range of 7–17 µΩ m. The measurements also showed TE figures-of-merit, ZT, at room temperatures ( T = 300 K) of 0.97 and 0.56, for thin films of Bi 2 Te 3 and Sb 2 Te 3 , respectively (equivalent to a power factor, PF, of 4.87 mW K −2 m −1 and 2.81 mW K −2 m −1 ). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO 2 ), an electrolyte of lithium phosphorus oxynitride (Li x PO y N z , known as LiPON) and a cathode of lithium cobaltate (LiCoO 2 , known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper.