Issue 11, 2024

Cluster-doping in silicon nanocrystals

Abstract

Creating tin-alloyed silicon nanocrystals with tailored bandgap values is a significant challenge, primarily because a substantial concentration of tin is essential to observe useful changes in the electronic structure. However, high concentration of Sn leads to instability of the silicon–tin nanocrystals. This work introduces a completely new approach to doping and the modification of the electronic structure of nanoparticles by incorporating few-atom clusters in nanocrystals, deviating from isolated atom doping or attempting alloying. This approach is exemplified via a combined theoretical and experimental study on tin (Sn) ‘cluster-doping’ of silicon (Si) nanocrystals, motivated by the opportunities offered by the Si–Sn system with tailored band energy. First-principles modelling predicts two noteworthy outcomes: a considerably smaller bandgap of these nanocrystals even with a modest concentration of tin compared to an equivalent-sized pure silicon nanocrystal and an unexpected decrease in the bandgap of nanocrystals as the diameter of nanocrystals increases, contrary to the typical quantum confined behaviour. Experimental verification using atmospheric pressure microplasma synthesis confirms the stability of these nanocrystals under ambient conditions. The plasma-synthesised nanocrystals exhibited the predicted atypical size-dependent behaviour of the bandgap, which ranged from 1.6 eV for 1.4 nm mean diameter particles to 2.4 eV for 2.2 nm mean diameter particles.

Graphical abstract: Cluster-doping in silicon nanocrystals

Supplementary files

Article information

Article type
Communication
Submitted
24 May 2024
Accepted
28 Aug 2024
First published
29 Aug 2024
This article is Open Access
Creative Commons BY license

Nanoscale Horiz., 2024,9, 2042-2050

Cluster-doping in silicon nanocrystals

A. U. Haq, M. Buerkle, B. Alessi, V. Svrcek, P. Maguire and D. Mariotti, Nanoscale Horiz., 2024, 9, 2042 DOI: 10.1039/D4NH00235K

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