Microstructure and nanomechanical properties of chemically etched gold nanoparticles

We show that chemical etching markedly alters the mechanical response of gold nanoparticles produced by solid-state dewetting. Both pristine and etched particles exhibit similar microcompression behavior: an initially elastic-like regime followed by an abrupt displacement burst, with pre-burst stresses in the gigapascal range characteristic of nucleation-controlled plasticity. However, etched particles display anomalously high pre-burst strains, reaching up to 45%. We demonstrate that etching introduces a high density of nanopores and stacking fault tetrahedra, which act as exhaustible dislocation sources. Their progressive annihilation during loading produces an elastic-like response, explaining the unusually large pre-burst deformations observed in etched nanoparticles.