Hot-injection Colloidal Synthesis and Characterization of Nanocrystalline Marcasite Iron Ditelluride {FeTe}$_{\mathrm{\mathbf{2}}}$

Colloidal semiconductor nanocrystalline (NC) materials are promising functional materials for advanced opto-electronic applications. Iron dichalcogenide nanocrystals such as iron pyrite (FeS$_{\mathrm{2}})$ have been successfully applied as hole transport material to enhance the performance of solar cells. Here, we report a hot-injection colloidal synthesis of NC iron ditelluride (FeTe$_{\mathrm{2}})$ using iron (II) bromide as an iron source and elemental tellurium (Te). The synthesized NC FeTe$_{\mathrm{2}}$ are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) imaging, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. These NC FeTe$_{\mathrm{2}}$ exhibit orthorhombic crystal structure in marcasite phase. The SEM images show irregular shape and size, and based on the EDS analysis, the average atomic ratio of tellurium (Te) to iron (Fe) is 2.04. Additionally, we discuss optical and electronic properties of thin films of these as-synthesized NC FeTe$_{\mathrm{2}}$ and its possible application.