A technique relates to manufacturing a nanogap. An oxide layer is disposed on top of a substrate. A release layer is disposed in a pattern on top of the oxide layer. A patterned trench is etched into the oxide layer using the pattern of the release layer. A metal layer is disposed on the release layer and in the patterned trench. A polish removes the release layer, thereby removing both the release layer and a portion of the metal layer having been disposed on top of the release layer, such that the metal layer remaining includes a first metal part and a second metal part connected by a metal nanowire. The metal layer remaining is coplanar with the oxide layer. A nanochannel is formed in the oxide layer in a region of the metal nanowire. The nanogap is formed in the metal nanowire separating the first and second metal parts.