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.

The nanoscale profiling modes of epitaxial GaAs layers are experimentally studied through focused ion beams (FIB). The regularities of the influence of ion current and single FIB exposure time on the...

A thermodynamic analysis of processes of interphase interaction in the Ga–As–O system has been performed and their theoretical laws have been determined, taking into account nonlinear thermal...

The kinetic Monte Carlo method is used to study the initial stage of GaAs molecular beam epitaxial growth on the GaAs(001) surface via fluxes of Ga atoms and As tetramers. The developed algorithm allows efficient investigation of the effects of the V/III flux ratio upon the geometrical characteristics of islands in the temperature range at which the (2 × 4) reconstruction of GaAs(001) is exclusively observed. The island density increases with an increasing V/III flux ratio, whereas the average island size decreases. The temperature dependences of the island characteristics are observed to be stronger at a smaller V/III flux ratio because large arsenic fluxes compensate the enhanced desorption at high temperatures. The island size distribution is more uniform at small V/III flux ratios, while a higher concentration of small clusters is observed as the arsenic flux increases. The analysis of the island morphology and size distribution function suggests that an increase in the V/III flux ratio and a decrease in the substrate temperature have similar effects upon island characteristics, which are attributed to suppression of surface diffusion in both cases.