[25p-F307-1~16] 6.4 Thin films and New materials

▼ [25p-F307-13] Growth of Uniaxially Oriented Nickel Aluminum Superalloy Films for Spectroscopic Infrared Emitters

〇(D)PhuocToan Tran^1,2, Duc Thien Ngo^1,2, Tadaaki Nagao^1,2 (1.NIMS, 2.Hokkaido University)

Keywords:nickel aluminum, superalloy

We report uniaxially oriented nickel aluminum (NiAl) superalloy films grown by DC magnetron sputtering under in situ heating, followed by subsequent reactive ion etching to fabricate spectroscopic mid-infrared emitters. We adopted NiAl – Al₂O₃ – NiAl trilayers design where the top NiAl strips acts as infrared resonators with their resonance wavelengths also matching to the periodicity of the NiAl strips. The films self-organize in (110) orientation with relatively low surface roughness and tight grain boundaries in columnar structure. The plasmonic performance of the NiAl absorbers (NAs) was found to be comparable to that of a NiAl single crystal and exceeds those of conventional refractory materials (molybdenum, tungsten, titanium nitride) in the visible to the NIR region (Fig. 1 (b)). The fabricated NAs that followed the simulated design exhibited excellent resonant absorption (absorptivity ≈ 92%) and single-band emission, as well as good resonance tunability by changing the periodicity and the width of the NiAl strips. This work paves the way to superalloy-based plasmonic photothermal energy applications.