  Scalability and foundry compatibility (as for example in conventional silicon
based integrated computer processors) in developing quantum technologies are
exceptional challenges facing current research. Here we introduce a quantum
photonic technology potentially enabling large scale fabrication of
semiconductor-based, site-controlled, scalable arrays of electrically driven
sources of polarization-entangled photons, with the potential to encode quantum
information. The design of the sources is based on quantum dots grown in
micron-sized pyramidal recesses along the crystallographic direction (111)B
theoretically ensuring high symmetry of the quantum dots - the condition for
actual bright entangled photon emission. A selective electric injection scheme
in these non-planar structures allows obtaining a high density of
light-emitting diodes, with some producing entangled photon pairs also
violating Bell's inequality. Compatibility with semiconductor fabrication
technology, good reproducibility and control of the position make these devices
attractive candidates for integrated photonic circuits for quantum information
processing.
