  Distributed Bragg reflectors (DBRs) composed of an AlN/GaN superlattice were
demonstrated for the first time on Si (100) substrates. Single-crystal wurtzite
superlattice structures were achieved on this cubic substrate by employing
offcut Si (100) wafers with the surface normal pointing 4{\deg} towards the
[110] direction. This misorientation introduced an additional epitaxial
constraint that prevented the growth of a two-domain GaN surface as well as
cubic GaN inclusions. A crack-free 600 nm GaN cap / 5x AlN / GaN DBR structure
on Si (100) was demonstrated. This accomplishment of a wurtzite III-nitride
DBRs on Si (100) opens the possibility to integrate novel optical and
optoelectronic devices with established Si microelectronics technology.
