Performance and spectral response of Pb1-xSnxTe(In) far-infrared photodetectors

We have compared directly the performance of a Pb1-xSnxTe(In) photodetector with that of two other state-of-the-art far-infrared detectors: a Si(Sb) blocked impurity band (BIB) detector and a Ge(Ga) photoconductor in an integrating cavity. The Pb1-xSnxTe(In) photodetector has current responsivity S-I several orders of magnitude higher than the Si(Sb) BIB at wavelength lambda=14.5 mu m. Persistent photoresponse with S(I)similar to 10(3) A/W at 40 mV bias and 1 s integration time at the wavelengths lambda=90 and 116 mu m has also been observed in the Pb1-xSnxTe(In) photodetector. This is larger by a factor of similar to 100 than the responsivity of the Ge(Ga) photoconductor in the same conditions. (C) 2000 American Institute of Physics. [S0003-6951(00)05120-2].