| 초록 |
High-temperature thermal treatment is a fundamental method to enhance the crystallinity or to recover its intrinsic properties of nanomaterials. However, the indirect and time-consuming conventional heating methods have hindered high-quality material production with thermally weak inclusions or its applicability due to limited treatment temperatures of such as transparent or flexible substrates. Here, it is introduced the microwave ‘induction’ heating as a selective and fast heating method for conductive thin film. In different with the conventional microwave dielectric heating for electrically polarized molecules, the microwave induction heating has a mechanism that strong current induced by an oscillating magnetic field in giga-hertz frequency generates ohmic heat in conduction thin film. A 20nm-thick silver thin film sputtered on a 5mm-thick glass substrate for low thermal emissivity coating has been selectively heated more than 550oC in 200ms without thermal damage by the microwave induction heating, while the temperature of the glass substrate is maintained around room temperature. The surface resistance of the silver thin film is reduced to near 30% due to crystallinity enhancement, in results, reflectance in the IR region and transmittance in the VIS region are increased. |
