Silicon Nanophotonics
Synthesis and Optical Properties of Silicon Nanowires
Students: AlexGuichard, LinyouCao, RohanKekatpure
Synthesis of Si nanowires
Most established: Vapor-Liquid-Solid Mechanism (VLS)
Au nanoparticles catalyze the decomposition of
gas Au and Si form a liquid phase alloy above the eutectic temperature
Decomposition of
causes a supersaturation of the Au/Si alloy particle Si nanowires grow from the supersaturated alloy
Au nanoparticle size determines the diameter of the nanowire
Au is a deep trap in Si, causing fast non-radiative decay!
Other materials can act as growth catalysts
Nanowire furnace with flashlamp heating
Light emission from oxidized TiSi2- and Co-catalyzed wires
Oxidation shrinks wire core diameter, induces confinement
passivates Si wire surface
PL decay lifetimes are roughly 10 us
Emission consistent with emission from Quantum confinement of carriers in the crystalline Si nanowire core.