For many optical and electrical devices, semiconductors made from a variety of bulk materials play a key role in device fabrication and application. In particular, bulk Si became widely used due to its low toxicity, fabricability, and good electrical and mechanical properties. Recently, the focus of research has shifted from bulk to nanoscale materials due to enhanced electrical and optical properties observed at the nanoscale. Many popular semiconducting nanomaterials such as CdSe and PbS are highly toxic posing a problem in the fabrication of biological and advanced technological devices such as bio-imaging and solar cells. Therefore, Si nanomaterials are very attractive for these types of nano-fabricated devices. Unfortunately, group IV semiconductors like Si have an indirect energy gap hindering their ability to interact with light efficiently. To address this issue, the energy gap can be transformed from an indirect to a direct energy gap as a result of quantum confinement effects as well as alloying with tin. This also allows for energy gap tunability which has been demonstrated successfully on other group IV semiconducting nanomaterials such as Ge1–xSnx nanocrystals (NCs). Bulk Si has a larger bandgap than Ge meaning that Si1–xSnx NCs will allow for even more tunable luminescence and energy gaps in the visible and IR spectrum. Herein, we will discuss the method by which we produced Si1–xSnx alloy NCs as well as characterization performed to probe the crystal structure, size, composition, photoluminescence, and energy gaps of the resulting NCs with varying tin compositions.

Synthesis and characterization of colloidal Si1–x Snx alloy nanocrystals with tunable energy gaps

ACS Spring 2022

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