IMPACT OF STRUCTURE ON PHOTOGATING

In previous reports, we predicted with computer simulation that photoc arriers from blue bias light can contribute under certain conditions t o the quantum efficiency in the red wavelength part of the spectrum fo r hydrogenated amorphous silicon (a-Si:H) p-i-n and Schottky barrier s tructures. We termed this phenomenon photogating and subsequently expe rimentally verified its existence by demonstrating red wavelength quan tum efficiency > 1 under blue bias light. In this report, we show how device structure affects this photogating and affects the wavelength r anges where it can appear. We show with computer simulations that cert ain structures can display a complementary phenomenon of blue quantum efficiencies > 1 under red bias light and discuss supporting experimen tal data. (C) 1996 American Institute of Physics.