  Bottom-up grown nanomaterials play an integral role in the development of
quantum technologies. Among these, semiconductor nanowires (NWs) are widely
used in proof-of-principle experiments, however, difficulties in parallel
processing of conventionally-grown NWs makes scalability unfeasible. Here, we
harness selective area growth (SAG) to remove this road-block. We demonstrate
large scale integrated SAG NW circuits consisting of 512 channel
multiplexer/demultiplexer pairs, incorporating thousands of interconnected SAG
NWs operating under deep cryogenic conditions. Multiplexers enable a range of
new strategies in quantum device research and scaling by increase the device
count while limiting the number of connections between room-temperature control
electronics and the cryogenic samples. As an example of this potential we
perform a statistical characterization of large arrays of identical SAG quantum
dots thus establishing the feasibility of applying cross-bar gating strategies
for efficient scaling of future SAG quantum circuits.
