Experimental observation of near-field thermal radiation between dielectric/organic multilayers

With the rapid advancement of nanotechnology, nanoscale devices have been widely utilized in various fields such as computing, communication, energy utilization and so on. In these devices, near-field thermal radiation (NFTR) attracts much attention due to its great application potential in energy utilization and conversion at the nanoscale. However, challenge still exists since the manufacture of micro-nano structures heavily depends on the property of substrate, making it a technical bottleneck to ensure the integrity of sample. In order to reduce the requirement for using substrate in NFTR, we propose to introduce the organic material into multilayer structures to change the surface profile, and experimentally investigate the NFTR between two dielectric/organic multilayers consisting of SiO2 and photoresist ROL-7133 with a gap spacing of similar to 200 nm. The measured heat flux enhancements over the blackbody limit are found to be similar to 5 times for the six-layer SiO2/photoresist, and the two-layer configurations with thicker SiO2 demonstrates similar to 12-fold enhancements. The underlying physical mechanisms behind the heat transfer enhancement are analyzed by the dispersion relation. Moreover, the variation of photoresist layer is demonstrated to modulate NFTR distinctly. These findings contribute to a more feasible application of NFTR and are expected to inspire further insights into adaptive nanoscale devices.