Insight into negative trions binding energy behavior inside type-I and reversed type-I core/shell quantum dots: A variational analysis

Abstract

Many body interactions between single particles inside low-dimensional semiconducting materials play a critical role in their optical characteristics. Within this context, tuning trionic and excitonic binding energy enables tailoring of the optical band gap of a given material. In this paper, we theoretically investigated the binding energy (Eb) of negatively charged excitons inside GaN/AlN type-I, and AlN/GaN inverted type-I core/shell quantum dots. Firstly, we started our study by examining the variation in the energy of electrons (holes) according to the change in the internal and external radii { as a means to obtain an insight into the energetic behavior of non-correlated single particles inside the two understudied nanosystems. The feature of the radial probability density distribution of confined single particles and negative trions is also discussed. Afterwards, we examined the impact of the heteronanodot spatial parameters (core radius and shell thickness) on the binding energy of confined trions. A comparison between the Eb behavior of negative trions inside core/shell type-I, and reversed type-I nanodots is also highlighted. Our results exhibit a strong dependence of the negative trion binding energy on the core material size and the shell thickness, and on the core-to-shell band mismatch as well. The obtained data also show the opportunity of modulating the negatively charged exciton correlation energy in a broad range extending from 220 to 650 meV . That paves the way for new optoelectronic devices based on III-Nitride core/shell quantum dots.