Nonlinear high-frequency hopping conduction in two-dimensional arrays of Ge-in-Si quantum dots: Acoustic methods

TL;DR

This paper investigates nonlinear high-frequency hopping conduction in 2D Ge-in-Si quantum dot arrays using acoustic methods, revealing charge transfer in clusters and charge heating as key mechanisms.

Contribution

It introduces acoustic measurement techniques to analyze nonlinear AC conductance and models the conduction mechanisms in dense localized state lattices.

Findings

Charge transfer within large clusters dominates AC conduction.

Charge heating by absorbed power causes non-Ohmic behavior.

Nonlinear conductance is linked to large localization length.

Abstract

Using acoustic methods we have measured nonlinear AC conductance in 2D arrays of Ge-in-Si quantum dots. The combination of experimental results and modeling of AC conductance of a dense lattice of localized states leads us to the conclusion that the main mechanism of AC conduction in hopping systems with large localization length is due to the charge transfer within large clusters, while the main mechanism behind its non-Ohmic behavior is charge heating by absorbed power.