Narrow‐Band Thermal Emitter with Titanium Nitride Thin Film Demonstrating High Temperature Stability

Abstract

generation, [4][5][6] radiative cooling, [7] and thermophotovoltaics (TPVs). [8] When selective thermal emitters are intended to emit in shorter mid IR range (e.g., an emitter for TPV system), the emitter has to be heated above one thousand kelvin. [9] Refractory metals such as molybdenum (Mo) [10] and tungsten (W) [11] are required in such cases. However, searching for alternative plasmonic materials is essential for reducing the material cost as well as for material research interest.Transition metal nitrides such as titanium nitride (TiN) and zirconium nitride (ZrN) also possess melting point as high as ≈3000 °C, [12][13][14] hence regarded as good candidate materials for thermal emitters. In addition, transition metal nitrides are regarded as alternative plasmonic materials in the visible to infrared region due to their high carrier concentrations up to 10 21 -10 22 cm −3 . [15] Among transition metal nitrides, TiN receives many attentions as an alternative plasmonic material in the past decades. [16][17][18] One of the advantages of using TiN is that it can be used in much higher temperature than other plasmonic materials. [19][20][21] However, there are only limited studies on thermal emitters using TiN so far.To demonstrate wavelength selective thermal emission, nanostructures have been investigated intensively [22,23] rather than microcavity structures which have been studied in 1990's and early 2000's. [24][25][26] Variety of nanostructures have been proposed, such as 1D grating, [27,28] 2D or 3D metallic photonic crystals, [2,29,30] and metal-insulator-metal (MIM) metamaterial structures. [31] Among those nanostructures, MIM metamaterial structures are easy to achieve wavelength selective emissions with single or multibands whose bandwidths and emission wavelengths are adjustable. [32] However, the requirement of nanofabrication, such as e-beam lithography, leads to limitations in large area fabrications.In contrast, thin-film based devices are the candidates for large area samples which do not require nanopatterning. [33,34] One way to optimize 1D thin film structures is via manipulating the phase-shifting layers in Gires-Tournois resonator. [35] Several different multilayer thin-film designs have been explored, which include Fabry-Perot cavity with either distributed Bragg reflectors (DBRs) and/or metallic mirror(s) and Tamm plasmon polaritons (TPPs) structures. For MIM structures (i.e., Fabry-Perot cavity), standing waves exist within the dielectric layer to form a cavity resonator. [36][37][38] In contrast, 1D TPP structure can excite TPP resonance at the interface of a A refractory wavelength selective thermal emitter is experimentally realized by the excitation of Tamm plasmon polaritons (TPPs) between a titanium nitride (TiN) thin film and a distributed Bragg reflector (DBR). The absorptance reaches nearly unity at ≈3.73 μm with the bandwidth of 0.36 μm in the experiment. High temperature stabilities are confirmed up to 500 and 1000 °C in ambient and in vacuum, respectively. When the TiN TPP stru...

Crystal Orientation-Dependent Oxidation of Epitaxial TiN Films with Tunable Plasmonics

“…On one hand, an ultrahigh vacuum condition is generally required during the growth of TiN thin films . On the other hand, devices with TiN operated at high-temperature usually need to be carefully vacuumed, , sealed in inert gases, or covered by an optically transparent protective layer . Previous studies have pointed out that the oxidation level of TiN is mainly controlled by temperature, oxygen partial pressure, and time. − Although several studies have indicated the impact of crystallographic orientation on the chemical reactivity of materials (metals, transition metal oxides, and organic materials), − its role in the oxidation of TiN thin films and resultant plasmonic performance is still unclear yet due to the lack of high-quality epitaxial TiN films with various controllable crystallographic orientations on the same substrates.…”

Tamm Plasmon‐Polariton Ultraviolet Lasers

“…In this work, the ZnO film is only 1/10 the thickness of the wavelength, and only half the thickness of the traditional microcavity structure. [43] Because the TPP mode has the ability to confine the electric field in the surface between DBR and metal, light, and matter can interact in such a small space to form polaritons. Polaritons can condensate at the ground state through stimulated scattering, forming polariton emissions.…”

Plasmonic Nanostructures for Photothermal Conversion

“…A few designs utilizing metal nitrides as high‐temperature solar‐thermal converter have been demonstrated. [ 141–143 ]…”