Electron and hole impact excitation of Er in MBE grown Si:O and Si 1− yC y diodes

Abstract

We have investigated the doping and electroluminescence (EL) properties at 1.54 μm of erbium ions in Si:O and Si 1− y C y :Er layers completely grown by MBE. Erbium in Si 1− y C y :Er films shows a lower doping density ( p=+1.6×10 17 cm −3) than erbium in Si:O ( n=−3×10 18 cm −3). The energy levels responsible for doping and optical erbium activation are different because different activation energies are observed. To realise both maximum luminescence output and low doping concentration, it is important to incorporate the carbon on substitutional lattice sites. The efficiency for electron and hole excitation by impact processes is compared. Electrons are about 5000× more efficient for impact excitation of Er 3+ than holes.