Optimisation of FIR photoconductors for atmospheric spectroscopy

The optimization of far infrared photoconductive detectors for use in balloon-borne or satellite-borne limb sounding atmospheric spectrometers was investigated. Instruments of this kind find important applications in the study of stratospheric chemistry, and the influence of anthropogenic pollutants. The choice of detector type for a given spectral region, and the optimization of the operational parameters (temperature, bias voltage, readout electronics) to achieve the best detector performance (detective quantum efficiency, speed of response) are considered. Results are presented for Ge:Ga, Ge:Sb, Ge:Be, Ge:Zn, bulk photoconductors, and for Si:Sb BIB detectors

Optimisation of FIR photoconductors for atmospheric spectroscopy

The optimization of far infrared photoconductive detectors for use in balloon-borne or satellite-borne limb sounding atmospheric spectrometers was investigated. Instruments of this kind find important applications in the study of stratospheric chemistry, and the influence of anthropogenic pollutants. The choice of detector type for a given spectral region, and the optimization of the operational parameters (temperature, bias voltage, readout electronics) to achieve the best detector performance (detective quantum efficiency, speed of response) are considered. Results are presented for Ge:Ga, Ge:Sb, Ge:Be, Ge:Zn, bulk photoconductors, and for Si:Sb BIB detectors

<title>Low compensation impurity band photoconductors</title>

Low compensation thin layer of antimony doped silicon impurity band photoconductors doped at the level 1017 - 1018 cm-3 are evaluated in moderate background photon flux in the range of 1012 s-1 with the goal to approach photon noise limitation operation in spectral ranges near 300 cm-1. Blocked impurity band photodetectors based on the same active layer geometry and thickness than the photoconductors were also implemented and measured. Spectral features including cut off wavenumbers specific to impurity band effects are investigated as a function of electric field and temperature. Spectroscopic evidence for a giant gain mechanism for photoelectrons excited from residual impurities in the blocking layer of BIB structure is found. Figures of merit of both IB and BIB elements were measured and physical mechanisms underlying the limitation of their performances are outlined