Effect of nanoscale ripples on the formation of ZnO quantum dots

Abstract

Nano-scale ripples on Si (100) substrates were prepared by argon ion beam sputtering at 6, 8, and 10 keV with an ion fluence of 5 × 1017 ions/cm2. The spatial wavelength of the nano-scale ripple increases as the ion beam energy increases, regardless of ion beam incident angles, indicating that ion beam induced diffusion is the dominant diffusion mechanism. ZnO quantum dots (QDs) with diameters less than 20 nm and heights less than 4 nm can be prepared over the temperature range from 200 ∼ 300 °C by reactive ion beam sputter deposition. Compared with ZnO QDs deposited on Si substrates without nano-scale ripple, the ion-beam textured substrate provides a wider processing window, improved dot size, and increased QD density.