Optimisation of growth parameters for photonic crystal structures

The preferential facetting that occurs during regrowth on patterned substrates by MBE, together with the different adatom migration lengths on different facets has been successfully used to provide good 1D confinement following overgrowth on mesas. However, in some instances it is preferable that the initial surface profile remains unmodified during successive growth stages. An example of this is for photonic crystal structures which can be created by patterning the surface with an array of mesas, and then regrowing a sequence of alternating layers of different refractive indices with spatially varying periodicity of order of hundreds of nanometers in both the lateral and growth directions.