Oxygen enhancement of 1.54 mu m Er3+ luminescence in hydrogenated amorphous silicon

摘要

The influence of the hydrogen content and the oxygen content on the luminescence from erbium-implanted hydrogenated amorphous silicon (a-Si:H) is presented. The Er3+-related emission is correlated to the efficiency of Er3+ optical centres with the bandgap variation and was found to depend strongly on the hydrogen content in the films. A direct correlation between the optical gap energy of the semiconductor and the hydrogen film content was observed. Moreover, the direct role played by oxygen impurities in the erbium optical activation was clearly evidenced. This effect is due to the higher oxygen content (1-2 at.%) and to the oxygen incorporation into a-Si:H during low-temperature annealing under an oxygen flow. Thus oxygen incorporation into a-Si:H films considerably enhances the photoluminescence intensity at room temperature and produces an increase in the value of the optical gap up to 2.1 eV. [References: 17]