LOW TEMPERATURE INFRARED PHOTOCONDUCTORS.
Summary rept. 31 May 66-30 Jun 67,
RCA LABS PRINCETON N J
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Results obtained in the continuation of research directed toward the development of an infrared-sensitive solid-state photoconductive multiplier are reported. The principal effort has been devoted to the investigation of the suitability of amorphous Se as a material of which the carrier-accelerating layer might be made. Such a layer must permit the acceleration of carriers of one sign to energies of the order of 1 eV and, if possible, not transmit carriers of the opposite sign. The selective transport of holes excited by photon absorption in photoconductors in contact with evaporated amorphous Se films has been sought using several different photoconductors. Selectivity, to varying degrees, has been observed in some cases but not in all. Special emphasis has been placed on the use of PbTe as a photoconductor having properties similar to those of PbTe-SnTe or PbSe-SnSe planned for ultimate use. The lack of reproducibility in the transport experiments is felt to be due to uncontrolled variation in properties of the Se films. This is based on an apparent correlation between poor selectivity and abnormally low resistivity of the Se layers. The low resistivity is thought not to be due to conversion of the Se but may be associated with strains due to thermal mismatch on cooling. A method of detection of energetic carriers emerging from a Se layer based on extrinsic impact ionization of GeCu at liq. He temperature has been devised. The first test was inconclusive. Recently, the investigation of Si as a material for the accelerating layer has been started. Author
- Electrical and Electronic Equipment
- Solid State Physics