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 doped by ion implantation has been studied. The results are compared with data for films doped from the vapor phase. A substantial difference in the dependences of the photoconductivity on the doping level for phosphorus and boron is detected. The photoconductivity of phosphorus-implanted films increases with the doping level and is an order of magnitude lower than the photoconductivity of films doped with phosphorus from the vapor phase. At the same time, the photoconductivity of boron-implanted films depends only slightly 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 recombination model that allows for the difference in charge transfer of the defect states in n- and p-type films. (C) 1999 American Institute of Physics. [S1063-7826(99)01603-8].