Strain-engineered photoluminescence of confined Ag nanocrystals

Abstract

Ag nanocrystals confined in amorphous Al2O3 and HfO2 matrices were fabricated using the pulsed laser deposition method and rapid thermal annealing technique. It is found that the microstructures and photoluminescence of Ag nanocrystals are closely related with strain. The compressive strain existing at the Ag nanocrystals in Al2O3 matrix is much stronger than that in HfO2 matrix. Consequently, at the same growth conditions, the size and bonds lengths of the Ag nanocrystals grown in Al2O3 matrix are smaller than those of Ag nanocrystals grown in HfO2 matrix. Moreover, less nonradiative defects at the surface of Ag nanocrystal confined in HfO2 matrix than those of Ag nanocrystals grown in Al2O3 matrix are induced by the strain, which leads to significantly enhanced PL of Ag nanocrystals confined in HfO2 matrix. The present findings indicate the opportunity to actively engineer and enhance the optical properties of silver nanocrystals through the application of strain engineering.