Monte Carlo Simulation of Gallium Droplet Motion on Vicinal GaAs(111) Substrates with Different Misorientation Directions

The influence of temperature, droplet size, direction and misorientation angle of vicinal GaAs(111)A substrates on the motion of Ga droplet, formed during the annealing under Langmuir evaporation conditions, is analyzed using Monte Carlo simulations. It is demonstrated that the droplet velocity increases with temperature and decreases with increasing droplet size. It is found that at the fixed droplet size the Ga droplet velocity is higher on surfaces with the misorientation in $[01 \overline{1}]$ and $[0 \overline{1} 1]$ directions than in the $[\overline{2} 11]$ direction. The step structure of the vicinal surfaces misoriented in these directions is different. This results in a different step arrangement during the annealing. Steps on the surface misoriented in the $[\overline{2} 1 1]$ direction become more winding than on the surfaces misoriented in $[01 \overline{1}]$ and $[0 \overline{1} 1]$ directions. It is shown, that during the annealing, gallium droplets form local step bunches on vicinal GaAs(111)A substrates with high misorientation angles. It is shown that the bunch height is determined by the gallium droplet size and is independent of the surface misorientation angle.