Nanowire Composite Thermoelectric Devices

This paper discusses the design, fabrication and testing of a novel thermoelectric device comprised of arrays of silicon nanowires embedded in a polymer matrix. By exploiting the low thermal conductivity of the composite and presumably high power factor of the nanowires, a high figure of merit should result. Arrays were first synthesized using a vapor-liquid-solid (VLS) process leading to one-dimensional growth of single-crystalline nanowires. To provide both structural support and thermal isolation between nanowires, parylene, a low thermal conductivity and extremely conformal polymer, was embedded within the arrays. Mechanical polishing and oxygen plasma etching techniques were used to expose the nanowire tips and a metal contact was deposited on the top surface. Scanning electron microscopy pictures illustrate the results of the fabrication processes. Using the 3ω technique, the effective thermal conductivity of the nanowire matrix was measured.