Thermoelectrical devices based on bismuth-telluride thin films deposited by direct current magnetron sputtering process

Devices based on multiple thermocouples of n-type and p-type semiconducting Bi2Te3 materials processed by photolithographic patterning are presented. Configurations parallel to the substrate have been investigated. A maximum generated voltage of 0.5 V has been obtained using a thermal difference of 36 K for a device made of 35 n-p junctions. Eventhough the output power with this in plane configuration is too low to envisage cooling or thermogeneration application, the feasibility of thermoelectrical devices based on thin films deposited by direct current magnetron sputtering is proved. The contact resistance of several metals has been studied. Ti as contact electrode allows more than 200 times contact resistivity reduction after an annealing at 473 K. This value leads to a calculated power generated by the 5 n-p device close to 0.7 μW under a temperature difference of 36 K. Such maximum value has to be considered for the development of autonomous systems based on thermal harvesting.