Hole Array Perfect Absorbers for Spectrally Selective Midwavelength Infrared Pyroelectric Detectors

We demonstrate a hybrid plasmonic–pyroelectric device operating as an uncooled midwavelength infrared detector with narrowband spectral selectivity. The device consists of a plasmonic perfect absorber with a built-in pyroelectric ZnO layer: It consists of a ZnO layer sandwiched by a Au microhole array as a top electrode and a Pt bottom electrode as a template for the uniaxially grown ZnO film. The geometrical design of the plasmonic Au (hole array)/ZnO/Pt system is determined by the numerical electromagnetic simulation and then fabricated by colloidal-mask lithography combined with reactive-ion etching. The fabricated detectors exhibit excellent spectral selectivity at the predesigned plasmonic resonances, which are tunable by changing the Au hole diameters. The results obtained here open up a route for realizing a new type of uncooled spectroscopic infrared detectors with a compact design and simple fabrication process.