THE INFLUENCE OF ILLUMINATION UPON ELECTROPHYSICAL PARAMETERS OF CDTE SAMPLE CONTACTS

Voltage−current characteristics (VIC′s) were investigated and electric resistivity  and  Hall coefficient measurements  of high−ohmic cadmium telluride samples were made at room temperature. The samples were cut from ingots grown by traveling heater method and  doped with chlorine (2 • 1017 cm−3 in load). Indium and  gold were used as contact materials. Galvanomagnetic measurements  were made at  square−form samples using the  Van der  Pau  method in magnetic fields B ≤ 1.5 Tl. The near−contact regions were illuminated by white light of variable intensity; the  VIC′s were investigated also. In addition, the VIC′s were investigated when the sample was illu- minated by monochromatic 480 nm light through gold−covered sides of the sample. The experiments showed that  illumination  of the  near−contact region leads to a considerable decrease of sample resistance (by 2—3 orders of magnitude). The VIC′s had linear shapes and in most cases came through the  origin of coordinates. With an increase in the light intensity the angle between the X−axis and the VIC straight line increased. Similar results were obtained when monochromatic light passed through gold−covered sides of the sample. We show  that  illumination  of the  near−contact region allows measuring the electrical resistivity and the Hall coefficient of the sample which is impossible without illumination.

cadmium telluride near−contact region illumination, electrical resistivity, Hall coefficient, voltage−current characteristics

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