Wideband infrared trap detector based upon doped silicon photocurrent devices.

We have designed, fabricated, and measured infrared trap detectors made from arsenic-doped silicon (Si:As) blocked impurity band (BIB) photodetectors. These trap detectors are composed of two detectors in a wedge geometry, with an entrance aperture diameter of either 1 or 3 mm. The detectors were calibrated for quantum efficiency against a pyroelectric reference detector using a Fourier transform spectral comparator system, and etalon effects and spatial uniformity of the traps were also quantified. Measurements of the traps at a temperature of 10 K show that nearly ideal external quantum efficiency (>90%) can be attained over much of the range from 4 to 24 μm, with significant responsivity from 2 to 30 μm. The traps exhibited maximum etalon oscillations of only 2%, which is about 10 times smaller amplitude than those of the single Si:As BIB detectors measured under similar conditions. Spatial nonuniformity across the entrance apertures of the traps was about 1%. The combination of high detectivity, wideband wavelength coverage, spectral flatness, and spatial uniformity make these trap detectors an excellent reference detector for spectrally resolved measurements and radiometric calibrations over the near- to far-infrared wavelength range.