Ujjwal Dhakal | Searcharxiv

arXiv2026

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

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 $\mathrm{μm}$-long nanowires with a height of 36 nm exhibited resistances of approximately 10 k$Ω$. 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.

cond-mat.mes-hall↗

arXiv2025

Crystallization Behavior of ZBLAN Glass Under Combined Thermal and Vibrational Effects: Part I -- Experimental Investigation

ZBLAN glass is a promising material for infrared optical fibers due to its wide transmission window and low theoretical attenuation. However, its strong tendency to crystallize during processing limits optical performance. While microgravity environments have been shown to suppress crystallization, the role of mechanical vibration under normal gravity conditions remains poorly understood. This study systematically investigates the influence of vibration on the crystallization behavior of ZBLAN using a controlled heating and vibration apparatus. Samples were subjected to varied thermal and vibrational conditions, and their crystallization onset and morphological evolution were examined through optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM). Results show that vibration reduces the crystallization onset temperature, indicating enhanced atomic mobility and nucleation kinetics. Progressive morphological transitions from needle-like to bow-tie and feather-like crystals were observed with increasing temperature and vibration intensity. Surface roughness analysis corroborates these findings, revealing a significant increase in nanoscale roughness in crystallized regions. Although brief exposure duration and partial thermal decoupling introduced variability among samples, the overall results confirm that vibration acts as a direct facilitator of nucleation rather than a purely thermal effect. This work provides new insight into vibration-induced crystallization in fluoride glasses and establishes the experimental foundation for follow-up modeling and apparatus optimization studies under terrestrial and microgravity conditions.

cond-mat.mtrl-sci↗