We design and characterize a photonic crystal (PhC) based silicon electro-optic modulator. The device is composed of a
planar photonic crystal with associated input and output dielectric waveguides and a p-i-n diode to inject free carriers for
index modulation. The photonic crystal, which confines light using the self-collimation phenomenon, has two regions of
varying air hole diameters forming a defect area in a host self-collimation lattice. At the interface of the defect with the
host lattice, an impedance mismatch is formed which is modulated using free carrier injection. With sufficient index
modulation the impedance mismatch is large enough to decrease the transmission through the defect region, thus,
modulation the overall transmission of the device. Our analysis shows that with a doping concentration in the range of
10<sup>20</sup>/cm<sup>3</sup>, the injected free carrier concentration can exceed 2.5*10<sup>19</sup> with a drive voltage of 2.6 V. This free carrier
concentration is sufficient to modulate the refractive index, Δn, greater than .05, which in turn produces a modulation
depth greater than 75%. A fabricated device produces a modulation depth of 80% with a drive current of 4mA.
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.