Field dependent electroluminescence from amorphous Si/SiNx multilayer structure

Abstract

We report field dependent electroluminescence (EL) from as-deposited amorphous Si/SiNx multilayer structure, where a-Si well layer thickness ranges from 1 to 4 nm, while SiNx barrier layer thickness is fixed at 3 nm. When the sample is applied by a low forward voltage Vbias (<6 V, i.e., 2.5 MV/cm), the dominant peak of EL is located at the lower energy region from 740 nm shifted to 660 nm with reducing the thickness of the a-Si well layer from 4 to 1 nm. However, under a high applied Vbias(>6 V), another EL band at the higher energy region is observed to be peaked at about 530 nm, which is independent of the well layer thickness. Photoluminescence (PL) investigation performed under optically pumped by the 325 nm line and the 488 nm line, respectively, also demonstrates the pump energy dependence of PL peaks. We interpreted these interesting phenomena of electrical and optical pump energy dependence of light emission by using different luminescence mechanisms in the a-Si/SiNx multilayer structure.