A technique is provided for manufacturing a nanogap in a nanodevice. An oxide is disposed on a wafer. A nanowire is disposed on the oxide. A helium ion beam is applied to cut the nanowire into a first nanowire part and a second nanowire part which forms the nanogap in the nanodevice. Applying the helium ion beam to cut the nanogap forms a signature of nanowire material in proximity to at least one opening of the nanogap.