Opposite effects of doping on nanoindentation pop-in phenomena in InAs and Ge crystals

Abstract

Doping in semiconductors not only modulates their electrical properties but also influences their mechanical behavior, such as nanoindentation pop-in phenomena. However, the underlying mechanisms of how doping affects pop-in events remain under debate. Here, we report the opposite effects of doping on the nanoindentation pop-in phenomena in InAs and Ge using nanoindentation, atomic force microscopy (AFM), and density functional theory (DFT) calculations. For InAs, the pop-in events disappear after doping with Zn and S, due to a reduction in energy barriers for dislocation nucleation, as revealed by the comparison of γ-surface energy. In contrast, pronounced pop-in events appear in Ge after doping with Ga and Sb, indicating an increase in stored elastic energy before phase transition in Ge. This research enhances our understanding of doping effects on the onset of plastic deformation, offering insights into the connection between the electronic structures and mechanical properties of semiconductors.