Effects of gamma irradiation on electroluminescence spectra from Au/amorphous Si/SiO 2 superlattices/p-Si structures

Abstract

Amorphous-Si/SiO 2 superlattices have been grown using the two-target alternation magnetron sputtering technique. The thickness of the SiO 2 layers in all the superlattices was 2.0 nm and that of the Si layers in nine types of the superlattice ranged from 0.6 to 3.8 nm in steps of 0.4 nm. Visible electroluminescence (EL) spectra of Au/amorphous-Si/SiO 2 superlattices/p-Si structures with Si layers of nine different thicknesses showed a peak located at 650 nm. After gamma irradiation, the EL peak increased 2.5 times in intensity. Moreover, a strong new 470 nm blue peak emerged from the EL spectra in all the Au/amorphous-Si/SiO 2 superlattices/p-Si structures. The experimental results indicate that the EL recombination process mainly originates from luminescence centers in the SiO 2 layers rather than from the Si layers in the superlattices.