  Diamond is a material of choice in the pursuit of integrated quantum photonic
technologies. So far, the majority of photonic devices fabricated from diamond,
are made from (100)-oriented crystals. In this work, we demonstrate a
methodology for the fabrication of optically-active membranes from
(111)-oriented diamond. We use a liftoff technique to generate membranes,
followed by chemical vapour deposition of diamond in the presence of silicon to
generate homogenous silicon vacancy colour centers with emission properties
that are superior to those in (100)-oriented diamond. We further use the
diamond membranes to fabricate high quality microring resonators with quality
factors exceeding ~ 3000. Supported by finite difference time domain
calculations, we discuss the advantages of (111) oriented structures as
building blocks for quantum nanophotonic devices.
