Theoretical study on passivation of small CdS clusters

Abstract

We use density functional theory quantum chemical calculations to model optical properties of small cadmium sulphide clusters in order to explore the formation of trap states and the possibility to achieve surface passivation. The addition of capping oxygen ions on the surface of the CdS quantum dots is found to passivate the single-bonded Cd atoms. Added Cu ions resulted in the formation of deep trap states for certain locations of the copper impurity, while removal of single-bonded Cd atoms by adding S or SH groups leads to a band gap increase.

Keywords:

• quantum dots
• TD-DFT
• passivating agent
• cadmium sulphide

Acknowledgements

The authors would like to thank Prof B.F. Minaev (Bogdan Khmelnitsky National University in Cherkassy) for discussion of the work. This work was partially supported by Erasmus Mundus Action 2 Target project.

Additional information

Funding

The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at Akka cluster of the High Performance Computing Center North (HPC2N), through the project ‘Multiphysics Modeling of Molecular Materials’[SNIC 020/11-23].