Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Density changes in amorphous silicon induced by swift heavy ions



Sjoerd Roorda, Amelie Lacroix, Stephanie Codsi, Gabrielle Long, Fan Zhang, Steven Weigand, Christina Trautmann


Pure and gold-doped amorphous silicon membranes were irradiated with swift heavy ions (75 MeV Ag or 1.1 GeV Au ions) and studied by small angle X-ray scattering. The samples that were irradiated with 1.1 GeV Au ions produced a scattering pattern consistent with core-shell type ion tracks of 2.0 ± 0.1 nm (core) and 7.0 ± 0.3 nm (total) radius irrespective of gold doping and consistent with radii previously observed [1]. The density in the core is nearly 4 % different from that of the surrounding material. Because the compressive stress required to maintain a 4% compacted core would exceed the yield strength of amorphous Si, the core must be less dense rather than more dense than the matrix. The entire track (core + shell) is slightly less dense than the surrounding material, putting it under a lateral stress consistent with the macroscopic "hammering" deformation seen when tracks overlap. No tracks were found in samples irradiated with 75 MeV Ag ions, and no signature specific to the gold impurity doping could be observed.
Physical Review B


Roorda, S. , Lacroix, A. , Codsi, S. , Long, G. , Zhang, F. , Weigand, S. and Trautmann, C. (2022), Density changes in amorphous silicon induced by swift heavy ions, Physical Review B, [online],, (Accessed April 20, 2024)
Created October 4, 2022, Updated November 29, 2022