Analytical Impact-Excitation Theory of Er/O/B Codoped Si Light-Emitting Diodes

Er doped Si light-emitting diodes may find important applications in silicon photonics and optical quantum computing. These diodes exhibit an emission efficiency 2 orders of magnitude higher at reverse bias than forward bias due to impact excitation. However, physics of impact excitation in these devices remains largely unexplored. In this work, we fabricated an Er/O/B codoped Si light-emitting diode which exhibits a strong electroluminescence by the impact excitation of electrons inelastically colliding the Er ions. An analytical impact-excitation theory was established to predict the electroluminescence intensity and internal quantum efficiency which fit well with the experimental data. From the fittings, we find that the excitable Er ions reach a record concentration of 1.8×10^{19}  cm^{-3} and up to 45% of them is in an excitation state by impact excitation. This work has important implications for developing efficient classical and quantum light sources based on rare earth elements in semiconductors.