Light-annealing effect on a-Si:H photodiode with the Ar laser-irradiation

The light stability of a-Si:H photodiode is much improved by light-annealing treatment, which is produced by the Hg-sensitized photochemical vapor deposition method. The dark-current density of the photodiode with light-annealing (2 h, 180 °C) is about seven times smaller than that without light-annealing after Ar laser irradiation (λ=514 nm, ∼6 W/cm2, 7 min). On the other hand, the photodegradation property of the photocurrent is not improved by light-annealing for a-Si:H single layer. Although the defects are produced by light-annealing around the mid-gap level of a-Si:H(i) film, the a-Si:H(i)/a-SiC:H(p) boundary of the photodiode is considered to be improved in the case. The electric field of a-Si:H(i) is considered to become strong, which decreases the dark-current density of the photodiode after Ar laser exposure.