Far-infrared spectrally selective LiTaO3 and AlN pyroelectric detectors using resonant subwavelength metal surface structures. (September 2020)

• Record Type: Journal Article
• Authors: Arose, Christopher; Terracciano, Anthony C.; Peale, Robert E.; Gonzalez, Francisco Javier; Loparo, Zachary; Cetnar, John; Vasu, Subith S.
• Is Part Of: MRS advances. Volume 5:Number 39(2020)
• Page Start: 2005
• Page End: 2012
• Publication Date: 2020-09
• Subjects: Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/adv.2020.291
• Languages: English
• ISSNs: 2059-8521

Abstract

Abstract: Plasmonic near-perfect absorbers, comprising metal films with a periodic array of subwavelength openings, were deposited on the surface of pyroelectric materials to create wavelength-selective far-infrared detectors. The detectors fabricated and investigated were based on one of two pyroelectric materials: (i) z-cut monocrystalline lithium tantalate (LiTaO3 ) wafers or, (ii) reactively sputtered aluminum nitride (AlN), with absorbers fabricated by contact photolithography. Spectrally selective absorption resonances were demonstrated by Fourier-transform spectroscopy. Spectrally-selective photoresponse was demonstrated with a tunable THz backward wave oscillator. Responsivity was estimated using a black body source to be ∼ 1 mV/W for AlN samples and ∼ 100 mV/W for LiTaO3 samples. Most similar work has focused on detectors for mid-wave and long-wave infrared spectral regions. Our focus on THz wavelengths beyond 20 μm is motivated by specific security and contraband sensing applications.