# Light absorption coefficient of an ordered array of spherical quantum dot chains

## TL;DR

This paper investigates the light absorption properties of ordered spherical quantum dot chains in a GaAs/AlGaAs system, revealing how absorption varies with frequency, polarization, temperature, and quantum dot size.

## Contribution

It provides a detailed analysis of intersubband electron transitions and their impact on absorption characteristics in quantum dot chains, including effects of polarization and material composition.

## Key findings

- Two maxima of absorption coefficient at band edges.
- Maximal absorption at the center between subbands, slightly temperature-dependent.
- Absorption bandwidth increases as quantum dot radius decreases.

## Abstract

We considered intersubband electron transitions in an array of one-dimensional chains of spherical quantum dots in the GaAs/Al$_{x}$Ga$_{1-x}$As semiconductor system. The absorption coefficient caused by these transitions was calculated depending on frequency and polarization of incident light and on Fermi level position, and temperature. We established the existence of two maxima of the absorption coefficient at the edges of the absorption band. It is shown that the absorption coefficient reaches its maximal value at the center of the region between the $s$-, $p$-like subbands and slightly varies with temperature. The change of the direction of the linearly polarized light wave incident on the chains from perpendicular to parallel leads to a sharp narrowing of the absorption band. It is obtained that the absorption bandwidth increases with the reduction of the quantum dot radius. We also analyzed the dependence of the absorption coefficient of GaAs/Al$_{x}$Ga$_{1-x}$As superlattice on concentration of aluminium in the matrix.