A cathodoluminescence study of the influence of the seed particle preparation method on the optical properties of GaAs nanowires

摘要

Cathodoluminescence at 8K is used to compare the optical properties of AlGaAs-capped GaAs nanowires, grown by metalorganic vapour phase epitaxy and seeded by gold particles prepared by different methods. Six different methods were used to fabricate and deposit gold seed particles onto GaAs substrates: colloid particles, aerosol particles and particles defined by electron beam lithography. The nanowires were grown with and without an insitu annealing step prior to the nanowire growth. The morphology showed no significant differences between the nanowires. The emissions from ensembles of nanowires have the same peak position, irrespective of seed particle type. Without the insitu annealing step prior to the nanowire growth, there are significant differences in the emission intensity and emission patterns from nanowires grown from different seed particles. When an insitu annealing step is included, all the resulting nanowires show identical optical emission intensity and emission patterns. This shows the importance of using an insitu annealing step prior to growth. This study demonstrates that different preparation methods for gold seed particles can be used to produce GaAs nanowires with highly similar optical properties. The choice of particle preparation method to be used can therefore be based on availability and cost.