Photo-thermovoltaic effects induced by CO_2 laser illumination of PbTe-metal junctions

摘要

Our study is concerned with the photo-thermovoltaic effects caused by the absorption of CO_2 laser light in narrow gap A~(Ⅳ)B~(Ⅵ) semiconductors. We report on results of experimental study of photoresponse induced in n-type and p-type lead telluride with Ni contacts. We show that in the case of ohmic contacts (n-PbTe-Ni and p-PbTe-Ni at 300K) the detected signal originates from thermoemf due to created crystal lattice temperature gradient. In the case of p-PbTe-Ni at 80K we have Schottky contacts and the photoresponse consists at least of two components: fast and great in value photoemf - due to carrier generation resulting from two-photon absorption, and slow as well as of lower magnitude thermoemf.