Impedance Spectroscopy of GeSn-based Heterostructures

In this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the basic semiconductor equations. We developed a numerical formalism based on a drift-diffusion model including a trap level and applied it to typical GeSn-based heterostructures by focusing on the electrical response under small-signal alternating current regime. The results demonstrate that our method provides an access to both microscopic and macroscopic properties, and thereon, to a physical interpretation of the electrical characteristics of GeSn-based structures by linking measurable quantities to micro-scale variations in the structures.