Method for equalization of temperature-induced non-uniformities in microbolometer IR FPA response based on use of
variations of preliminary heating and measuring bias pulses applied both to sensitive and compensating bolometers is
proposed. Carried out numerical simulation of proposed FPA architecture demonstrates high quality of signal
equalization over wide temperature range that allows to apply microbolometer FPA indoors without use of any additional
measures such as temperature stabilization and real-time correction.
The technology of high-quality microbolometer focal plane arrays (FPA) fabrication has been developed. Simple and cheap sol-gel technology of thermosensitive vanadium oxide layers preparation is underlain in its basis. Uncooled 160×120 microbolometer sensor assemblies for 8-14 microns spectral range have been fabricated. The paper brief outlines simple techniques to measure crosstalk, precision of FPA temperature stabilization and sensor assembly response time to infrared signal change. The noise equivalent temperature difference better than 100 mK has been achieved at frame rate 60 Hz and F/1 optics.
The technology of high-quality uncooled focal plane arrays (FPA) fabrication has been developed. Simple and cheap sol-gel technology of thermosensitive vanadium oxide layers preparation is underlain in its basis. Uncooled 160x120 and 320x240 FPA for 8-14 microns spectral range have been fabricated. The noise equivalent temperature difference less than 8OmK has been achieved at frame rate 60 Hz for 160x120 FPA and at use of optics with 1/1 relative aperture.
In this paper the experimental results on designing of 128X128 FPA for far IR spectrum range are presented. The module is a hybrid assembly of the photodetectors array based on GaAs/AlGaAs multiquantum wells and silicon multiplexer. The noise equivalent difference of temperature of the photodetector module NEDT=0.067 K at T=65 K.
GaAs/AlxGa1-xAs quantum well infrared photodetectors grown by molecular-beam epitaxy with x varied from 0.26 up to 0.43 are investigated. The huge increase of dark current (by 2 - 3 orders) in photodetectors with x approximately equals 0.4 after illumination of samples by optical radiation ((lambda) < 1.3 micrometers ) at lowered temperatures and the subsequent slow dark current relaxation are observed. The model of barriers with a local sag potential increasing tunnel current is proposed. The value of the sag potential is increased at optical ionization of unintentional deep levels in the barrier and is decreased at the subsequent capture of electrons from conduction band on deep levels. Analysis of the dark current kinetics allowed to determine some parameters of these deep levels.