Fabrication and characterization of silicon/silicon dioxide super lattices for silicon based light emitting devices

摘要

Silicon based light emitting materials are of particular interest for integrating electric and photonic devices into an all-silicon platform. The progress of nano-scale fabrication has led to the ability to realize silicon emitters based on quantum confinement mechanisms. Quantum confinement in nano-structured silicon overcomes the indirect bandgap present in bulk silicon allowing for radiative emissions. Two common structures that utilize the quantum mechanisms leading to light emission in silicon are nanocrystals embedded in silicon dioxide and silicon/silicon dioxide super lattices. Nanocrystals employ quantum confinement in three dimensions while the super lattice structure induces two-dimensional confinement. Strong photoluminescence (PL) has been demonstrated in both structures, confirming the presence of quantum confinement effects. Our super lattice structures are grown using plasma enhanced chemical vapor deposition (PECVD) with alternating layers of silicon and silicon dioxide. We present here sub-10nm period superlattices confirmed via transmission electron microscopy and x-ray diffraction and reflectivity. We also present a new design for an electrically pumped device along with preliminary current-voltage characteristics.