Pillar array structure with uniform and high aspect ratio nanometer gaps

1. An apparatus comprising:

an inlet configured to receive a fluid;

an outlet configured to exit the fluid; and

a nanopillar array connected to the inlet and the outlet, the nanopillar array configured to allow the fluid to flow from the inlet to the outlet;

wherein the nanopillar array includes nanopillars arranged to separate entities by size;

wherein the nanopillars are arranged to have a gap separating one nanopillar from another nanopillar;

wherein the gap is constructed to be in a nanoscale range;

wherein the nanopillar array comprises an oxide layer applied on the nanopillars, the oxide layer causing the gap to be uniform along a vertical axis of the one nanopillar and the another nanopillar; and

wherein the oxide layer causes unevenness in a diameter of the nanopillars to be uniform, resulting in the gap being uniform along the vertical axis of the one nanopillar and the another nanopillar.

2. The apparatus of claim 1 , wherein the one nanopillar is to a side of the another nanopillar, such that the gap is in between.

3. The apparatus of claim 1 , wherein the gap between the one nanopillar and the another nanopillar is uniform along a vertical axis of the one nanopillar and the another nanopillar.

4. The apparatus of claim 1 , wherein the oxide layer causes a size of the gap to be as small as about 20 nanometers while the gap remains uniform.

5. The apparatus of claim 1 , wherein an increase in a thickness of the oxide layer causes a decrease in a size of the gap.

6. The apparatus of claim 1 , wherein a size of the gap is less than 100 nanometers.

7. The apparatus of claim 1 , wherein a size of the gap is less than 300 nanometers.

8. The apparatus of claim 1 , wherein a monolayer is applied to the nanopillars to reduce a size of the gap; and

wherein the gap having a reduced size is configured to separate smaller entities relative to when the monolayer is not applied to the nanopillars.