Innovative Direction for Alloying and Doping of Layered Materials

Oren Meiron, Chemistry, Ben-Gurion University, Beer Sheva, Israel
Sekhar Reddy Ghanta , Chemistry, Ben-Gurion University, Beer Sheva, Israel
Ayala Cohen, Chemistry, Weizmann Institute, Rehovot, Israel
Maya Bar-Sadan, Chemistry, Ben-Gurion University, Beer Sheva, Israel

Layered transition metal dichalcogenides (TMDs) are well known materials. In recent years first principle calculations showed that doping and alloying of TMDs can be used in order to modify their electronic and magnetic structure. To date, TMDs doping and alloying is only performed at high temperature, solid state reactions, such as chemical vapor deposition (CVD). We have developed a low temperature, controllable solvothermal technique for producing doped and alloyed TMDs, specifically MoS₂. We have demonstrated the synthesis of Zr, Mn and Gd doped MoS₂ as well as MoS_2-xSe_x alloys. The Materials were analyzed using TEM, SEM, XRD, XPS, UV-Vis and Raman spectroscopy. Shift in the UV-Vis exciton peaks as well as in the XRD peaks suggests the formation of doped material or an alloy rather than two separate phases. ICP-MS analysis of the MoS_2-xSe_x alloys showed that increasing the selenium content in the reaction increases x in the alloy, supporting the UV-Vis data. We have demonstrated a new approach for controlled doping and alloying of TMDs using simple solvothermal technique. By controlling the doping and alloying degrees, the electronic properties of the TMDs can be optimized for a variety of applications such as photo catalysis, Li ion electrodes, super capacitors and many others.