Detection of 9.5 μm CO2 laser pulses in indium doped PbTe p-n junction

Abstract

A unique feature of the PbTe semiconductor is the growth of its forbidden energy gap with increasing temperature. This allows saving diode-typical characteristics at temperatures up to 180 K. PbTe p-n diodes were fabricated by means of indium donor diffusion into PbTe single crystals grown using the Czochralski technique. The dark saturation current density was ~10−5 A/cm2 at T = 100 K, whereas at T = 180 K it reached ~10−1 A/cm2. The photovoltage signals induced by a pulsed CO2 laser light across PbTe p-n junction were investigated over the 100–180 K temperature range. The two-photon absorption-caused photovoltaic effect is observed for the first time in In doped PbTe p-n junction for 9.5 μm wavelength at T = 100 K.