Narrow size distribution of Au nanocrystals formed in sapphire by utilizing Ar ion irradiation and thermal annealing

We describe a method to form narrow size distribution of Au nanoparticles in Al2O3 substrate. A layer of Au about 30 nm thick was deposited on surface of single crystalline Al2O3, and then was brought into the matrix by Ar ion irradiation to form Au nanoparticles. The size distribution of the nanoparticles was subsequently modified by annealing treatment. Rutherford Backscattering Spectrometry, X-ray Diffraction and Transmission Electron Microscopy were used to study the structure and the size distribution of the nanoparticles. The results show that a narrow size distribution of nanoparticles formed in single crystalline alumina with an average diameter of 3.9 nm and a standard deviation of 0.5 nm.