Improving the electrical conductivity of Pt nanowires deposited by focused electron beam induced deposition using thermal annealing

TL;DR

This study demonstrates that thermal annealing significantly improves the electrical conductivity of platinum nanowires fabricated by FEBID, making them suitable for low-temperature nanoelectronic applications.

Contribution

It introduces a thermal annealing process that enhances conductivity and purity of FEBID platinum nanowires, enabling their use in ultra-low-temperature electronics.

Findings

Electrical conductance increased by up to five orders of magnitude after annealing.

Resistances of nanowires decreased to approximately 10 kΩ at 36 nm height.

Resistances decreased monotonically with temperature down to 100 mK.

Abstract

We investigated the electrical conductivity of platinum nanowires with heights ranging from 2 nm to 200 nm, deposited by focused electron beam induced deposition (FEBID). Post-deposition processing was employed to enhance the electrical conductivity of the platinum nanowires. Thermal annealing of as-deposited nanowires in air at 225$^{\circ}$C for 4 hours increased electrical conductance by up to five orders of magnitude. After annealing, 22.5 $\mathrm{\mu m}$-long nanowires with a height of 36 nm exhibited resistances of approximately 10 k$\Omega$. This nanowire underwent a reduction in height to one-quarter of its original value, a reduction in width to one half, and a reduction in cross-sectional area by approximately one order of magnitude. The platinum-to-carbon weight ratio increased from 35:65 to 85:15. The electrical resistance decreased monotonically as temperature was lowered from room temperature to 100 mK, confirming that annealed FEBID platinum nanowires are promising building blocks for nanoelectronic devices operating at millikelvin temperatures.