@article{Wang2023, 
author = {Lei Wang and Shu Wang and Xiaofeng Wang and Jianming Zhang and Jianjie Dong and Bin Wei and Haiguang Yang and Zhongchang Wang and Ziyang Zhang and ChuanFei Guo and Qian Liu},
title = {Anomalous refinement and uniformization of grains in metallic thin films},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {12},
pages = {13358-13365},
keywords = {linear relationship, ripening, laser direct writing, anomalous refinement, localized heating},
url = {https://www.sciopen.com/article/10.1007/s12274-023-5902-9},
doi = {10.1007/s12274-023-5902-9},
abstract = {When a laser beam writes on a metallic film, it usually coarsens and deuniformizes grains because of Ostwald ripening, similar to the case of annealing. Here we show an anomalous refinement effect of metal grains: A metallic silver film with large grains melts and breaks into uniform, close-packed, and ultrafine (~ 10 nm) grains by laser direct writing with a nanoscale laser spot size and nanosecond pulse that causes localized heating and adaptive shock-cooling. This method exhibits high controllability in both grain size and uniformity, which lies in a linear relationship between the film thickness (h) and grain size (D), D ∝ h. The linear relationship is significantly different from the classical spinodal dewetting theory obeying a nonlinear relationship (D ∝ h5/3) in common laser heating. We also demonstrate the application of such a silver film with a grain size of ~ 10.9 nm as a surface-enhanced Raman scattering chip, exhibiting superhigh spatial-uniformity and low detection limit down to 10−15 M. This anomalous refinement effect is general and can be extended to many other metallic films.}
}