Amorphous silicon suboxide light-emitting diodes

Optical absorption was measured on undoped as deposited and annealed amorphous silicon suboxide (a-SiO_x:H) samples prepared by plasma enhanced chemical vapour deposition. The subgap absorption was reduced by one order of magnitude upon annealing. Annealing of a-SiO_x:H p-i-n structures at 250°C increased the forward current densities and shifted the dominant electroluminescence peak from 1.1 eV to 1.3 eV, indicating a change in the recombination mechanism due to a lower defect density in the intrinsic layer. The total electroluminescence efficiency increased by a factor of 3 upon annealing and reached ∼ 10^-3%.