Fabrication of flexible thermoelectric microcoolers using planar thin-film technologies

Abstract

The present work reports on the fabrication and characterization of a planar Peltier cooler on a flexible substrate. The device was fabricated on a 12 m thick Kapton(c) polyimide substrate using Bi 2 Te 3 and Sb 2 Te 3 thermoelectric elements deposited by thermal co-evaporation. The cold area of the device is cooled with four thermoelectric junctions, connected in series using metal contacts. Plastic substrates add uncommon mechanical properties to the composite film-substrate and enable integration with novel types of flexible electronic devices. Films were deposited by co-evaporation of tellurium and bismuth or antimony to obtain Bi 2 Te 3 or Sb 2 Te 3 , respectively. Patterning of the thermoelectric materials using lift-off and wet-etching techniques was studied and compared. The performance of the Peltier microcooler was analysed by infrared image microscopy, on still-air and under vacuum conditions, and a maximum temperature difference of 5 C was measured between the cold and the hot sides of the device.