PBSE PHOTODETECTOR ARRAYS FOR IR SENSORS

PbSe Linear arrays have been fabricated to be used as multiple LR gas sensors at room temperature. PbSe layers were obtained by thermal evap oration in vacuum on SiO2/Si wafers. Samples became photoconductive af ter a sensitization process that includes thermal treatments in an iod ine-enriched atmosphere. Both morphological features and chemical comp osition of the layers were studied along the different steps of the se nsitization process with a Scanning Electron Microscope. Photoelectric al measurements were also carried out, By comparison between microscop ic and photoelectrical measurements, some relations between changes in the morphology of the PbSe layers and changes in their photoconductiv e behavior were established. The dispersion observed in the photocondu ctive characteristics of the array elements is associated to the appea rance of inhomogeneities during the sensitization process. Whereas the presence of iodine in the sensitization process accelerates the recry stallization rate of PbSe, the presence of oxygen could be responsible for the photoconductivity. (C) 1998 Elsevier Science S.A.