Fabrication and characterization of ultrathin thermoelectric device for energy conversion

The fabrication of a micro/nano-scale thermoelectric module is very challenging. In this paper, a reliable and efficient hybrid fabrication method for ultrathin thermoelectric devices based on the non-contact exposing, photoresist melting and microfabrication technology is presented. The total thickness of the thermoelectric module is about 1 mu m. Twenty-one devices are fabricated successfully, of which each is composed of 127 pairs of thermoelectric legs connected in series with an average resistance of 25 Omega. Experimental results indicate that ultrathin thermoelectric device work stable and reliable, and demonstrate that the method presented is suitable for fabrication of thinner and higher integrality devices beyond TE devices in the micro-nanoscale range. Without a load and at the temperature of 150 degrees C, the output voltage and output current are 18.5 mV and 671.9 mu A, respectively; summarily, at the temperature of 50 degrees C the output voltage and current are 6.1 mV and 240.1 mu A, respectively. The peak output power density is 0.29 W/m(2) and 2.9 x 10(5) W/m(3). In addition, a one-dimensional heat transfer model is established to obtain a quantitative characterization for further numerical modeling. The present research can provide a useful guide for the design of a micro/nano-scale thermoelectric device in the near future.