Joanna Millunchick

Our goal is to determine the atomistic mechanisms for surface segregation in III-V semiconductor alloy systems. Surface segregation has significant technological impact, since it affects the interfacial abruptness and compositional uniformity in device structures. However, the details of atomic processes that govern surface segregation are still unknown, and a comprehensive theory for this phenomenon has not yet developed. Unlike the study of binary systems such as GaAs, InAs and InP, the ternary systems have been consistently underrepresented in scientific literature both experimentally and computationally despite its importance to optoelectronic device technology. We are investigating the surface atomistics through both experimental molecular beam epitaxy (MBE) growth coupled with in-situ STM as well as first-principle density functional theory (DFT) calculations using the Vienna Ab-initio Simulations Package (VASP). The primary focus of our simulations work is concerned with the surface reconstructions of ternary systems, mainly InGaAs and InGaSb, in both lattice-matched and strained epilayers.