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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.

Bolometric arrays dominate in commercial terahertz and millimeter wave imagers. Bolometers tend to be slow and require an operating bias that increases the power budget. This paper presents first results on antenna-coupled thermo-electric junction detectors, a potentially attractive alternative to microbolometers. The nanoscale junctions have small thermal mass and can be much faster than bolometers. These junctions are heated by currents excited in spectrally-selective antennas and generate a voltage based on the Seebeck effect without any externally applied power. A pixel comprising a series array of antenna coupled junctions with peak response at 7.5 THz (40 µm wavelength) is designed and experimentally demonstrated. Responsivity of 5 MV/W, 500 Hz chopping frequency, and D* of 3.5 x 1010 Jones are demonstrated.

Thermoelectric (TE) thin films have promise for harvesting electrical energy from waste heat. We demonstrate TE materials and thermocouples deposited by aqueous spray deposition on glass. The n-type material was CdO doped with Mn and Sn. Two p-type materials were investigated, namely PbS with co-growth of CdS and doped with Na and Na2CoO4. Seebeck coefficients, resistivity, and power generation for thermocouples were characterized.