Effective mobility for sequential carrier transport in multiple quantum well structures

TL;DR

This paper develops a theoretical model to accurately describe carrier mobility in multiple quantum well structures, simplifying complex carrier dynamics into an effective parameter compatible with existing models.

Contribution

It introduces analytical expressions for effective mobilities considering various transport mechanisms in MQWs, validated by experimental data, enhancing the understanding of carrier transport in these structures.

Findings

Effective mobilities align with experimental measurements.

Model covers thermionic emission and tunneling mechanisms.

Simplifies carrier dynamics for device modeling.

Abstract

We investigate a theoretical model for effective carrier mobility to comprehensively describe the behavior of the perpendicular carrier transport across multiple quantum well (MQW) structures under applied electric field. The analytical expressions of effective mobilities for thermionic emission, direct tunneling, and thermally-assisted tunneling are derived based on the quasi-thermal equilibrium approximation and the semi-classical approach. Effective electron and hole mobilities in InGaAs/GaAsP MQWs predicted from our model are in good agreement with the experimental results obtained from the carrier time-of-flight measurement near room temperature. With this concept, the complicated carrier dynamics inside MQWs can be simplified to an effective mobility, an equivalent parameter which is more straightforward to handle and can be easily incorporated in the conventional drift-diffusion model.