Near-Field Thermal Radiation between Two Plates with Sub-10 nm Vacuum Separation

Abstract

Radiation greatly exceeding blackbody between two objects separated by microscale distances has attracted great interest. However, challenges in reaching such a small separation between two plates have so far prevented studies below a separation distance of about 25 nm. Here, we report a study of radiation enhancement in the near-field regime of less than 10 nm between two parallel plates. We make use of bulk, rigid plates to approach small separation distances without the adverse snap-in effect, develop embedded temperature sensors to allow near-zero separation, and employ advanced sensing method to level the plates and approach and maintain small separations. Our findings agree with theoretical predictions between parallel surfaces with separations down to 7 nm where an 18000 times enhancement in radiation between two quartz plates is observed. Our method can also be used to explore heat transfer between other materials and can possibly be extended to smaller separation gaps.

Radiative heat transfer at the nanoscale: experimental trends and challenges

“…Spacers made of polystyrene beads 48,51 , pillars in SU-8 photoresist 56 or silica 49 , or suspended devices 72,73 were used, leading to fixed distances for many current large-area experiments. Currently best gaps are of the order of few tens of nanometers for these experiments, with a recent claim of having reached the sub-10 nm region 74 with piezoelectric alignment. Extremely flat samples (roughness less than 1 nm) are required, which is possible thanks to silicon technology, without any surface bowing.…”

Optimized Colossal Near‐Field Thermal Radiation Enabled by Manipulating Coupled Plasmon Polariton Geometry

“…[ 7 ] ), SiO 2 (from ref. [ 20 ] ) were also calculated. η of Gr/SU8/5L heterostructures is quite close to that of the infinite layers limit and remarkably better than that of all other structures within this gap distance range.…”

“…[ 7 ] ), and SiO 2 (from ref. [ 20 ] ). Graphene Fermi levels | E F | were set to 0.11 eV in the calculation.…”

Toward applications of near-field radiative heat transfer with micro-hotplates

“…Keeping two objects with a large temperature difference separated by only a few hundred nanometers remains a challenging task. Successful approaches include precise piezoelectric actuators with feedback control loops to keep both objects apart 16 – 18 or arrays of spacers between the surfaces 19 – 21 . The first option is difficult to scale to commercial applications as it requires bulky and expensive equipment, whereas the second implies high heat conduction losses through the spacers and mechanical stress from thermal expansion.…”