Staircase Quantum Dots Configuration in Nanowires for Optimized Thermoelectric Power

TL;DR

This paper demonstrates how optimizing the energy configuration and number of quantum-dots in nanowires can significantly enhance the power output of thermoelectric devices based on inelastic transport processes.

Contribution

It introduces a staircase energy configuration for quantum-dots that improves thermoelectric power, providing guidelines for device optimization.

Findings

Staircase energy configuration enhances power factor.

Optimal nanowire length depends on energy-step.

There is an optimal energy-step for maximum power.

Abstract

The performance of thermoelectric energy harvesters can be improved by nanostructures that exploit inelastic transport processes. One prototype is the three-terminal hopping thermoelectric device where electron hopping between quantum-dots are driven by hot phonons. Such three-terminal hopping thermoelectric devices have potential in achieving high efficiency or power via inelastic transport and without relying on heavy-elements or toxic compounds. We show in this work how output power of the device can be optimized via tuning the number and energy configuration of the quantum-dots embedded in parallel nanowires. We find that the staircase energy configuration with constant energy-step can improve the power factor over a serial connection of a single pair of quantum-dots. Moreover, for a fixed energy-step, there is an optimal length for the nanowire. Similarly for a fixed number of quantum-dots there is an optimal energy-step for the output power. Our results are important for future developments of high-performance nanostructured thermoelectric devices.