Effect of annealing temperature on the fabrication of self-assembled gold droplets on various type-B GaAs surfaces

Abstract

In this paper, the fabrication and detailed evolution process of self-assembled Au droplets on diverse GaAs type-B (n11) substrates, where n is 9, 7, 5, 4, and 2, are successfully demonstrated. The evolution process is systematically investigated by variation of the annealing temperature (T_a) from 250 to 550 °C. Self-assembled Au clusters begin to nucleate at 300 °C, and wiggly nanostructures with connected geometry are formed as a transitional stage at 350 °C. Between 400 and 550 °C, self-assembled Au droplets are successfully fabricated, and they show increased average dimensions and decreased density with increasing T_a, while showing improved size uniformity above 500 °C. Throughout the T_a range, the properties of the resulting Au droplets depend on the substrates utilized, and this is systematically analyzed in relation to the root mean squared (RMS) roughness.