Over the last decade, there has been a strong research interest in developing colloidal synthetic methods for the preparation of Group IV (Si, Ge) Nanocrystals (NCs). These indirect band-gap materials are of interest due to their relative low toxicity and abundance in the earth’s crust compared to conventional quantum dots containing toxic elements such as cadmium, lead and mercury.<br/>The composition of Ge NCs has been manipulated to improve and accommodate the electronic properties by increasing the charge carrier concentration. Among different methods to increase charge carriers in NCs such as irradiation, temperature and applying a biased electric field, doping these materials by using n-type dopants such as antimony and bismuth which can alter the Fermi energy level and consequently the band gap of these doped- NCs has been investigated. The resulting doped Ge NCs were characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM/STEM) and elemental mapping to determine the dopants distribution in Ge lattice was carried out at National Center for Electron Microscopy (NCEM) of Molecular Foundry at Lawrence Berkley National Laboratory using FEI Titan X microscope. The PXRD refinement data along with XPS, High Resolution STEM micrographs and elemental mapping show the successful incorporation of n-type dopants in both Ge lattice and on the surface of the NCs.

Composition manipulation of germanium nanocrystals via microwave-assisted colloidal synthesis

253rd National Meeting (2017)

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