Photoluminescence and optical characterization of a-Si_xN_1-x:H based multilayers crown by pecvd

摘要

High room temperature photoluminescence efficiency (PLE) was observed for the first time in a-Si_xN_1-x:H based nanometric multilayers deposited by plasma enhanced chemical vapour deposition (PECVD).The structue consists of alternate stoichiometric a-Si_3N_4:H barrier layer (E_0.4=5.0 eV) and well layers in which E_0.4 is varied between 2.11 eV and 2.64 eV.The peak of Pl spectra and the absorption coefficient edge exhibits a blue shift up to 0.5-0.6 eV by decreasing the well thickness from 30 A down to 5-10 A.A strong increase in the PLE of multilayers,with well thickness around 5-10 A, with respect to the PLE of bulk material was obtained.