Monte Carlo Free Energy of InGaAs 2x4 Reconstruction

Joanna Millunchick

The nanoscale surface structure of epitaxially grown III-V semiconductor alloys plays a significant role in interfacial properties and self assembly for optoelectronic devices. In order to determine the principles which give rise to various structures and how to direct their formation in synthesis, we are taking an approach which couples computation and experiment to study phase stability, two-phase coexistence, and disorder of III-V surface reconstructions. Monte Carlo simulation employing density functional theory (DFT) energy calculations is used to predict finite-temperature entropic effects on surface structure and composition of the InxGa1-xAs model system. These results are compared to experimental data from films grown via molecular beam epitaxy (MBE) and characterized in situ via STM.