PHOTODETECTION BY LIGHT-INDUCED BARRIER MODULATION IN Cu-DIFFUSED Au-CdS DIODES.

Modified Au-Cds:Cu Schottky barriers were prepared by diffusing Cu to a depth of 0. 1 to 0. 2 mu m into single crystals of CdS, prior to evaporating rectifying Au contacts. Modulation of essentially thermionic forward current by light-induced lowering of an electrostatic barrier leads to steady-state electron-per-photon gains in excess of 10**6 at light intensities lower than 5 multiplied by 10**1**1 photons cm** minus **2 sec** minus **1 where response times exceed 1 sec. Barrier-height determinations, in the dark and under illumination with 5000-A light, by means of internal photoemission, thermal activation energy, and J-V measurements, show unequivocally that under saturating light conditions the potential barrier is reduced by 0. 23 plus or minus 0. 03 V.