In addition to their intrinsic interest, some of the new families of coordination and organometallic compounds we have isolated are highly effective reagents for the chemical vapour deposition of thin film metal chalcogenide semiconductors. These constitute an important class of materials for many electronics and thermoelectric applications.
In a collaborative project with Prof. C. H. de Groot (Electronics and Computer Science) and Prof. A. L. Hector (Chemistry), we have exploited the specific advantages offered by our tailored reagents, which include their suitability for highly selective deposition onto micro- and nano-patterned regions on lithographically patterned substrates (Chemistry of Materials, 2013, 22, 4442-4449; doi:10.1021/cm302864x; J. Materials Chem. A, 2014, 2, 4865; doi:10.1039/c4ta00341a) and the ability to produce dense arrays of individual metal chalcogenide nanocrystals. The morphology, structure and crystallite orientation are identified using a combination of scanning electron microscopy, atomic force microscopy and thin film X-ray diffraction techniques. These materials exhibit very promising electrical and thermoelectric properties (Journal of Materials Chemistry C, 2105, 3, 423; doi:10.1039/C4TC02327G). Substrate selectivity is a feature that is not typical of CVD, and the origin of this behaviour is currently being investigated, as well as the prospects for utilising it in the fabrication of micro- and nano-devices for phase change memory and thermoelectric applications.
Similar approaches are being adopted for the growth of early transition metal selenide and telluride thin films.