Cathodoluminescence studies of GaAs nano-wires grown on shallow-trench-patterned Si.

The optical properties of GaAs nano-wires grown on shallow-trench-patterned Si(001) substrates were investigated by cathodoluminescence. The results showed that when the trench width ranges from 80 to 100 nm, the emission efficiency of GaAs can be enhanced and is stronger than that of a homogeneously grown epilayer. The suppression of non-radiative centers is attributed to the trapping of both threading dislocations and planar defects at the trench sidewalls. This approach demonstrates the feasibility of growing nano-scaled GaAs-based optoelectronic devices on Si substrates.

Observation of localized surface plasmons in spatially controlled array structures.

We observed the reflectance spectra of three different nano-scale array structures of Au-coated silicon nanorods. The trends of the reflectance spectra indicate that the localized surface plasmon modes can be spatially controlled by manipulating geometric parameters, namely the lattice constants of the array. In addition, the experimental results were compared with 2D numerical simulations based on the finite element method. Satisfactory agreement between the experimental observations and numerical results was obtained.