Electrical and thermal properties of silver nanowire fabricated on a flexible substrate by two-beam laser direct writing for designing a thermometer

Abstract

Accurate knowledge of electrical conductivity and thermal conductivity temperature dependence plays a crucial role in the design of a thermometer. Here, by using a two-beam laser direct writing system, an individual silver nanowire (AgNW) with well-defined dimensions is fabricated on a polyethylene terephthalate (PET) substrate. The temperature dependence of the resistivity of the fabricated AgNW is measured ranging from 10 to 300 K, and fitted with the Bloch–Grüneisen formula. The residual resistivity ((1.62 ± 0.20) × 10−7 Ω m) of the AgNW is larger than that of the bulk material (1 × 10−11 Ω m). The electron–phonon coupling constant of the AgNW is (1.08 ± 0.13) × 10−7 Ω m, which is larger than that of the bulk silver (5.24 × 10−8 Ω m). Moreover, the Debye temperature of the AgNW is 199.30 K and is lower than that of the bulk silver (235 K). The Lorenz number of the fabricated AgNW is found to decrease as the temperature increases. Besides, the Lorenz number (2.66 × 10−7 W Ω K−2) is larger than the Sommerfeld value (2.44 × 10−8 W Ω K−2) at room temperature. The measurement results allow one to design a thermometer in the temperature range 40–300 K. The flexibility of the AgNW is also excellent, and the resistance increase of the AgNW is only 2.58% when the AgNW bending about 1000 times with a bending radius of 1 mm.