Selective photoconductivity induced in PbTe(Ga) by a local phonon mode

Selective photoconductivity at frequency omega = 155 cm(-1) was discovered in PbTe(Ga) narrow-gap semiconductors at liquid-nitrogen temperatures. The corresponding energy is much lower than all characteristic energies of the electronic spectrum of the semiconductor. The effect is attributed to optical excitation of a local vibrational mode of an impurity center leading to delocalization of the electrons. (C) 1996 American Institute of Physics.