  We describe here the first comprehensive investigation of a pyroelectric
response of a p-n junction in a non-polar paraelectric semiconductor. The
pyroelectric effect is generated by the, temperature dependent, built-in
electrical dipole moment. High quality PbTe p-n junctions have been prepared
specifically for this experiment. The pyroelectric effect was excited by a
continuous CO2 laser beam, modulated by a mechanical chopper. The shape and
amplitude of the periodic and single-pulse pyroelectric signals were studied as
a function of temperature (10K-130K), reverse bias voltage (up to -500 mV) and
chopping frequency (4Hz-2000Hz). The pyroelectric coefficient is about 10^(-3)
microC/cm2K in the temperature region 40 - 80 K. The developed theoretical
model quantitatively describes all the experimental features of the observed
pyroelectric effect. The time evolution of the temperature within the p-n
junction was reconstructed.
