Bi-layered plasmonic photothermal nanocomposite heater for laser-irradiation based rapid digital annealing of metal and oxide films

Abstract

A photonic annealing technique implanting highly energetic photons provides the characteristic advantage of triggering designated chemical/physical evolutions in materials along with suppressing undesired side reactions in a kinetically controlled way. However, the effectiveness of the photonic annealing technique is determined essentially by the optical property of the material itself and can become almost negligible for optically transparent inorganic films. To resolve this critical impediment, we have designed a photothermal nanocomposite heater that can convert the optical energy into a thermal energy and can transfer efficiently the thermal energy to the target materials regardless of the optical properties of the materials. The photothermal nanocomposite heater is designed to have a bi-layered structure with a silver nanoparticle-populated dense bottom layer and a porous carbon upper layer. It is revealed by time-dependent photothermal simulation that the silver nanoparticles with a plasmonic absorption behavior have a significant role in generating the thermal energy from the photons implanted by the green laser irradiation process, while a number of air voids prevent the thermal energy from being dissipated into the outer surroundings. The digitally designable annealing is conducted up to temperatures as high as 800 degrees C at a ramping rate as fast as 1300 degrees C/sec. The thermal profiles including the temperature, duration time and heating/cooling rate are adjustable accordingly depending on the laser processing parameters of the laser power, scan speed and number of loops in a single scan. It is demonstrated that a photothermal heater-based green laser irradiation process enables a rapid digital annealing for optically different particulate metallic and vacuum-deposited oxide films, generating their conductive nature and highly improved ferroelectric property, respectively.