Self-limiting growth and bimodal size distribution of Au nanoislands on InAs(111)B surface

Abstract

Gold nanoparticles are widely used for catalytic growth of different semiconductor nanowires. It is important therefore to have a full appreciation of the factors influencing the size distribution of such particles on semiconductor substrates. Here, we describe some interesting phenomena observed during low-temperature deposition of Au onto InAs(111)B substrates where Au islands are solid. In particular, we find a bimodal character of the size distribution of these islands. We then develop a nucleation model which is based on a specific form of the island formation energy. The model yields a self-limiting growth behavior in which the growth rate of large islands is suppressed e.g. due to dislocations. We show that the regime of self-regulated nucleation with a few pulses is observed for short growth times, leading to a bimodal size distribution or even a more complex shapes. For longer growth times, the system acquires a steady-state regime with a time-independent supersaturation and hence the pulses disappear.