Broadband thin-film and metamaterial absorbers using refractory vanadium nitride and their thermal stability

Abstract

Strong absorption of the full spectrum of sunlight at high temperatures is desired for photothermal devices and thermophotovoltaics. Here, we experimentally demonstrate a thin-film broadband absorber consisting of a vanadium nitride (VN) film and a SiO2 anti-reflective layer. Owing to the intrinsic high loss of VN, the fabricated absorber exhibits high absorption over 90% in the wide range of 400-1360 nm. To further enhance the near-infrared absorption, we also propose a metamaterial absorber by depositing patterned VN square patches on the thin-film absorber. An average absorption of 90.4% over the range of 400-2500 nm is achieved due to the excitation of broad electric dipole resonance. Both thin-film and metamaterial absorbers are demonstrated to possess excellent incident angle tolerances (up to 60°) and superior thermal stability at 800 ℃. The proposed refractory VN absorbers may be potentially used for solar energy harvesting, thermal emission, and photodetection.

Scalable‐Manufactured Plasmonic Metamaterial with Omnidirectional Absorption Bandwidth across Visible to Far‐Infrared

“…The broadband absorbers with limited working angles (angular‐sensitive absorbers) are also included. [ 7,34–46 ]…”

“…The broadband absorbers with limited working angles (angular-sensitive absorbers) are also included. [7,[34][35][36][37][38][39][40][41][42][43][44][45][46] To stabilize the TiN NPs on the hierarchical coral Al substrate while retaining the superior optical properties, a 20 nmthick Al 2 O 3 protective coating layer is deposited on the coral-TiN BBA using atomic layer deposition (ALD) method. As shown by the AFM height mapping in Figure 4a, the TiN particle size increases conformally without abrupt morphology variation after ALD.…”

Transition Metal Nitrides Are Heating Up the Field of Plasmonics

“…Inorganic surface coatings composed of silicon oxide , and oxynitrides , have been used to minimize the oxidation of TiN and ZrN NPs and improve their LSPR. Substrate bound, precisely sized and shaped nanostructure arrays of TiN, VN, and HfN have been fabricated using electron beam lithography , and focused ion beam milling . These physical methods allow fine control over the nanostructure morphology, which is currently inaccessible through other synthetic methods; however, it is difficult to separate these nanostructures from the substrates and enable dispersion in solvents.…”

Optimizing broadband metamaterial absorber using deep reinforcement learning

“…Therefore, broadband metamaterial absorbers with various geometries have been studied extensively. [13][14][15][16][17][18] A typical geometry is a metal-insulatormetal, known as a perfect absorber. However, the uniform shape of the top metal structure exhibits only a narrow-band resonance.…”