EFFECT OF STRONG ILLUMINATION ON CURRENT-VOLTAGE CHARACTERISTICS OF AU SI, AL/SI AND SN/SI SCHOTTKY BARRIERS WITH NATIVE-OXIDE LAYER/

Light induced general degradation in the dark I-V characteristics of A u/Si, Al/Si and Sn/Si junctions at low temperature and at room tempera ture. Illumination caused changes in the interface and bulk properties of the investigated junctions, all of them prepared under identical c onditions. Their barrier heights, phi(B) change with increasing illumi nation time. The largest rate of degradation in phi(B) upon exposure t o light was observed for an Sn/Si junction (lowest phi(B)), whereas th e smallest change occurred with an Au/Si junction (highest phi(B)). At low temperature, upon turning off the light, the photogenerated curre nt of the Sn/Si sample exhibited faster recovery in reaching the initi al dark current (at t(ill) = 0) than the Al/Si junction; for the less reactive Au/Si sample, the presence of the oxide layer reduced the lea kage current and subsequently delayed recovery of the measured photocu rrent.