Influence of the Characteristics of the STM-tip on the Electroluminescence Spectra

TL;DR

This paper investigates how the shape and size of an STM tip influence the electroluminescence spectra of quantum dots, revealing a critical tip radius where spectral behavior transitions, with implications for nanoscale optoelectronic control.

Contribution

It introduces a detailed analysis of the impact of STM tip characteristics on electroluminescence spectra, highlighting a critical tip radius affecting spectral peak positions.

Findings

Electroluminescence peak positions are highly sensitive to tip radius and applied voltage.

A critical tip radius causes a transition in the trend of peak position changes.

The critical radius relates to confinement effects in the quantum dot.

Abstract

We analyze the influence of the characteristics of the STM-tip (applied voltage, tip radius) on the electroluminescence spectra from an STM-tip-induced quantum dot taking into account the many-body effects. We find that positions of electroluminescence peaks, attributed to the electron-hole recombination in the quantum dot, are very sensitive to the shape and size of the confinement potential as determined by the tip radius and the applied voltage. A critical value of the tip radius is found, at which the luminescence peak positions as a function of the tip radius manifest a transition from decreasing behavior for smaller radii to increasing behavior for larger radii. We find that this critical value of the tip radius is related to the confinement in the lateral and normal direction.