Photoconductivity of amorphous hydrated silicon doped by ion implantation

The effect of the concentration of impurities (phosphorus and boron) on the photoconductivity of films of amorphous hydrated silicon, hydrated and dop ed by ion implantation has been studied. The results are compared with data for films doped from the vapor phase. A substantial difference in the depe ndences of the photoconductivity on the doping level for phosphorus and bor on is detected. The photoconductivity of phosphorus-implanted films increas es with the doping level and is an order of magnitude lower than the photoc onductivity of films doped with phosphorus from the vapor phase. At the sam e time, the photoconductivity of boron-implanted films depends only slightl y on the doping level and virtually coincides with that of films doped with boron from the vapor phase. These results are explained in terms of a reco mbination model that allows for the difference in charge transfer of the de fect states in n- and p-type films. (C) 1999 American Institute of Physics. [S1063-7826(99)01603-8].