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.

Low-cost, light-weight, low-power, large-format, room-temperature, mid-wave infrared (MWIR) detectors are needed for reduced-scale aircraft. An opportunity, suggested by direct-read X-radiography systems, is the use of thin film transistor (TFT) array as read-out integrated circuit (ROIC) for low-cost sensors deposited directly and unpatterned onto this ROIC. TFTs have already been thoroughly optimized for power, weight, large-format, and cost by the flat-panel-display industry. We present experimental investigation of aqueous-spray-deposited, mid-wave-IR, metal-chalcogenide heterojunction CdS/PbS photodiodes for this application. Measured responsivity, detectivity D*, and photoresponse spectra are reported.

Silicon nanowires (SiNWs) were comprehensively characterized in dependence on conditions of their formation via metal (Ag) -assisted chemical etching (MACE) of monocrystalline Si. The Ag structures remained on/between SiNWs based on both n- and p-Si were found to promote surface enhancement of Raman scattering (SERS) from organic molecules adsorbed on their surface. The Ag structures on/between the SiNWs/p-Si facilitated two times higher SERS-signal from 10-6 M rhodamine 6G than those in the SiNWs/n-Si. The activity of the SERS-substrates based on p-Si was improved by modification with small Au dendrites, which provided rich family of hot spots and prevented degradation of the SERS-activity observed for pure Ag dendrites due to formation of Ag2S during one week of storage in air. The SERS-substrates based on the Au/Ag dendrites on SiNWs/p-Si allowed to achieve nanomolar detection limit of rhodamine 6G and 5,5′-dithiobis (2-nitrobenzoic acid).

In this paper, the light emission phenomena over solid-state incandescent light emitting devices have been modelled based on Planck's law of blackbody radiation. The emission spectra from the thermal excitation of nano-resistors with and without inclusion of an Indium Tin Oxide (ITO) or amorphous silicon (a-Si) thin film filter is simulated and compared with those measured from actual devices. The simulated emission spectra are further utilized to study the light characteristics for SSI-LED with ITO, a-Si and polycrystalline silicon (poly-Si) thin film filters.

Morpho-Butterfly inspired lamella structures were fabricated to make a multivariable optical sensor for measuring percent level concentrations of H2 and CO in a high temperature, zero-O2 environment. The SiO2 and Si3N4 3D structures were covered with gold nanoparticles (AuNPs) and cerium IV dioxide (CeO2) and exposed to varying concentrations of H2 and CO at 300°C. Experiments with AuNP sizes with an average diameter of 11 ± 3 nm and 3 ± 0.5 nm (larger and small AuNPs, respectively) showed that the larger AuNPs had a stronger response to the same concentrations of H2 and CO with less CO saturation and baseline drift. Further testing in the presence of 1% hydrocarbons (HCs) as an interfering gas showed excellent response to up to 17% H2 and CO in a zero-O2 environment with changes in reflected intensity of -13.1 ± 0.4% for H2 and -5.8 ± 0.3% for CO. The presence of HCs did not induce any baseline drift, with the total amount of drift being less than 0.5% over 13 hours of testing at 300°C.