Fabrication of A III B V nanostructures by droplet epitaxy has many advantages over other epitaxial techniques. Although various characteristics of the growth by droplet epitaxy have been thoroughly studied for both lattice-matched and mismatched systems, little is known about physical processes hindering the formation of small size InAs/GaAs nanostructure arrays with low density and thin wetting layer. In this paper, we experimentally demonstrate that the indium droplet diameter can be reduced by decreasing the deposition time, but this reduction is limited by a critical thickness of droplet formation dependent on the substrate temperature. Using the kinetic Monte Carlo model, we propose a mechanism considering that the droplet formation begins when the system overcomes a barrier determined by the substrate attraction. As a result of physical and chemical balancing between adatom aggregation and substrate wetting, this attraction becomes weaker with increasing either temperature or deposition amount, which leads to the critical layer formation and subsequent nucleation. Using this mechanism, it is possible to provide a wide control over the nanostructure growth which is especially important at high temperatures when the processes of the island ripening are particularly intensive.

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We study the droplet epitaxy of indium on the As‐stabilized GaAs(001) substrate using the analytical theory of nucleation combined with kinetic Monte Carlo simulations. The developed model allows considering the atomistic processes of nucleation and growth of droplets without strict binding to the zinc blende structure. We assume that the formation of stable droplets results from the alternation of the processes of assembly and disassembly of subcritical islands. We use a concept of nonmonotonic dynamics of critical size and supersaturation to explain the physical processes on the surface. The thickness of the indium wetting layer exceeds a value of one monolayer and increases gradually with decreasing temperature, which is due to the long‐range interaction of indium with the GaAs substrate. The simulation results are in good agreement with the experiments in a wide range of growth temperatures.

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