Uncooled long wave infrared photodetectors with optimized spectral response at selected spectral ranges

J. Piotrowski; Z. Orman; Z. Nowak; J. Pawluczyk; J. Pietrzak; A. Piotrowski; D. Szabra

doi:10.1117/12.606244

31 May 2005 Uncooled long wave infrared photodetectors with optimized spectral response at selected spectral ranges

J. Piotrowski, Z. Orman, Z. Nowak, J. Pawluczyk, J. Pietrzak, A. Piotrowski, D. Szabra

Proceedings Volume 5783, Infrared Technology and Applications XXXI; (2005) https://doi.org/10.1117/12.606244
Event: Defense and Security, 2005, Orlando, Florida, United States

Abstract

The performance of uncooled photodetectors operating in the middle and long wavelength spectral range is limited by the noise originated from thermal generation and recombination processes in semiconductors. The noise level exponentially increases with decreasing band gap of the semiconductor. Therefore, the uncooled short wavelength devices are characterized by good performance while the long wavelength ones are much less sensitive. The consequence is very poor performance of long wavelength devices at short wavelength range. We report here two-lead multilayer photoconductors that operate over a wide spectral band with performance improved by a large factor at short wavelength ranges. The devices consist of several stacked active regions (absorbers) with their outputs connected in parallel so the resulting output signal current is the sum of the signals generated at all active regions. Due to a high photoelectric gain in the wider gap absorbers and low thermal generation and recombination, the devices offer significantly better performance at short wavelengths while the long wavelength response remains essentially unaffected. The practical devices have been obtained using complex Hg_1-xCd_xTe heterostructures grown on CdTe or GaAs substrates by ISOVPE, MOCVD or combination of the two epitaxial techniques. An example is an uncooled photoconductor operating up to 11μm, with response at 0.9-4μm increased by ≈3 orders of magnitude in comparison to the conventional 11 μm device.

Citation Download Citation

J. Piotrowski, Z. Orman, Z. Nowak, J. Pawluczyk, J. Pietrzak, A. Piotrowski, and D. Szabra "Uncooled long wave infrared photodetectors with optimized spectral response at selected spectral ranges", Proc. SPIE 5783, Infrared Technology and Applications XXXI, (31 May 2005); https://doi.org/10.1117/12.606244

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