Effect of magnetic field on donor impurity-related photoionisation cross-section in multilayered quantum dot

ABSTRACT

The effect of the magnetic field on the electron states in the Al${}_{0.3}$Ga${}_{0.7}$As/GaAs/Al${}_{0.3}$Ga${}_{0.7}$As multilayered quantum dot with and without shallow-donor impurity is under study. The magnetic field dependence of the impurity-related transition energies and the corresponding photoionisation cross-section is calculated, taking into account the excited states. The problem is solved using the effective mass approximation and rectangular potential profiles for wells and barriers using diagonalisation and finite element methods. The results obtained by both methods coincide with high accuracy. It is shown that the transition energies and photoionisation cross-section strongly depend on the impurity position and the magnetic field induction. As the magnetic field induction increases, all the peaks of photoionisation cross-section shift to the region of higher energies in the case of off-centre impurity and shift to lower energies in the case of on-centre impurity. The effect of merging two photoionisation cross-section peaks with increasing magnetic field induction is revealed, leading to a significant increase in the value of impurity photoionisation cross-section.

KEYWORDS:

• Photoionisation cross-section
• multilayered quantum dots
• donor impurity
• magnetic field

Acknowledgments

CAD is grateful to the Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and projects “Efectos de capas delta dopadas en pozos cuánticos como fotodetectores en el infrarrojo”, “Propiedades magneto-ópticas y óptica no lineal en superredes de Grafeno”, “Efectos ópticos intersubbanda, no lineales de segundo orden y dispersión Raman, en sistemas asimétricos de pozos cuánticos acoplados”, “Estudio de propiedades ópticas en sistemas semiconductores de dimensiones nanoscópicas” and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD exclusive dedication project 2020-2021). CAD also acknowledges the financial support from El Patrimonio Autónomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación Francisco José de Caldas (project: CD 111580863338, CT FP80740-173-2019).

Author contributions statement

The contributions of the authors are as follows:

M. V. Chubrey was responsible of the analytical and numerical calculations and writing of the manuscript.

V. A. Holovatsky proposed the problem and was responsible of the numerical calculations and writing of the manuscript.

C. A. Duque was responsible of the numerical calculations and writing of the manuscript.

Data availability statement

All the files with tables, figures, and codes are available. The corresponding author will provide all the files in case they are requested.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.