Pressure-dependent thermal conductivity transient measurement of graphene

The thermal properties of graphene determine the thermal damage evaluation of graphene diaphragm and the lifetime of graphene-based devices. The conventional transient measurement method tends to result in the lowprecision thermal conductivity (lc) for suspended monolayer graphene and complex interferometry setup. Hence, in order to improve lc measurement of graphene, a simple, miniaturized and portable Fabry-Perot (F-P) resonator with 10 -layer graphene is proposed to perform the actuation and vibration detection of the suspended graphene. Then, the lc value can be calculated by means of laser -heated graphene's thermomechanical response, along with the established model for thermal time constant (tau) of a uniformly heated circular film. A quadratic fit is applied to the measured lc at different air pressures and an average fitting curve is obtained, thus determining that the measured lc relatively decreases by 13.32% with the increasing air pressure outside the F-P cavity from -22 kPa to -101 kPa. Subsequently, the COMSOL heat transfer simulation confirms that convective heat transfer is the primary reason for the external air pressure affecting transient measurements of lc of graphene. Hence, after taking the intercept of the average fitting curve, the predicted lc at 0 Pa of 10 -layer suspended graphene is calculated to be 194.48 W/(m center dot K), which is close to the fitting curve calculated from previously reported lc of graphene with different layers. This study contributes to accurate transient measurement of lc in graphene, and is also instructive for investigating transient thermal process in other two-dimensional materials.