Colloidal Synthesis of Atomically thin CdSxSe1-x Alloyed Nanosheets through Control of Precursor Reactivity

G. S. Reddy, Chemistry, Ben-gurion University of the Negev, Beer Sheva, Israel
Pradipta Sankar Maiti, Chemistry, Ben-gurion University of the Negev, Beer Sheva, Israel
Noga Meir, Physics, Weizmann Institute of Science, Rehovot, Israel
Lothar Houben, Peter Grünberg Institute and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Julich, Germany
Maya Bar-Sadan, Chemistry, Ben-gurion University of the Negev, Beer Sheva, Israel

Atomically thin two-dimensional (2D) semiconductor nanostructures have attracted a lot of interest from many researchers in recent years due to their similar properties to quantum wells (QW). These structures can be easily prepared in solution phase with controlled and uniform thickness that is small compared to their lateral dimensions. These 2-D nanostructures have appealing combination of properties: physical properties close to the quantum wells and chemical properties similar to the colloidal quantum dots. Their optoeloctronic properties can be tuned smiply by varying the number of atomic layers. Furthermore, alloying these semiconductors also provide us additional degree of freedom which can be used to tune their properties by varying their composition. These alloyed semiconductors can open new possibilities in band gap engineering and as well as developing tunable emitters.

Here, we are going present the colloidal synthesis of the ultrathin 2D CdS_xSe_1-x nanosheets as well as their physiochemical properties. We  will be showing how the relative amount of S and Se can drastically affect the shape, size and optical properties of these structures. We will also present the C_c and C_s corrected high-resolution electron microscopy (HR-TEM) studies for these 2D systems. Structural, compositional and optical characterizations are going to be presented using UV-visible absorption and fluorescence spectroscopy, atomic force microscopy (AFM) and powder X-diffraction (PXRD).