Response to 'Comment on 'Highly sensitive heat flux sensor based on the transverse thermoelectric effect of YBa_2Cu_3O_(7-δ) thin film'' [Appl. Phys. Lett.119, 066101 (2021)]

摘要

Recently, Yang has commented our article. Here is our response to the comments.(1) Yang believed that the sensitivity of the heat flux sensor based on the transverse thermoelectric effect (TTE) of YBa_2Cu_3O_(7-δ) thin films was not very high compared with other sensors [like water-cooled Gardon gauge and atomic layer thermopile (ALTP) sensors].The area of the water-cooled Gardon gauge is πR~2 = 3.14 mm~2, which is much smaller than that of the TTE-based sensor (4×3 = 12 mm~2). Then, Yang incorrectly concluded that the sensitivity of our TTE-based sensor (220.9 μV cm~2/W) is smaller than the water-cooled Gardon gauge (180.3 μVcm~2/W) when considering their areas. The sensitivity of the water-cooled Gardon gauge is expressed as K_(Gardon) = CR~2/S, where C is a constant, R is the radius of foil, and S is the thickness of foil. However, the sensitivity of the TTE-based sensor is K_(TTE) =l/(2q)sin(2θ)|S_(ab) - S_c| ▽T_z, where l is the irradiation length, θ is inclined angle, ▽T_z is the temperature gradient, q is the heat flux density, and S_(ab) and S_c are the Seebeck coefficients in the ab-plane and along the c-axis, respectively. It is clearly seen that the sensitivity of the water-cooled Gardon gauge is proportional to the sensing area, whereas the sensitivity of the TTE-based sensor is proportional to the irradiation length. Thus, their sensitivities cannot be normalized quantitatively using the areas, as their mechanisms are significantly different.