Vapor-liquid-solid synthesis of Ag₂Te using chemical vapor deposition method

Silver telluride, Ag₂Te, has been selectively synthesized by conventional chemical vapor deposition (CVD) via the vapor-liquid-solid growth mechanism. The pre-deposited Ag film on the SiO₂/Si substrate was chemically reacted with vaporized Te atoms and transformed into liquid-phase Ag-Te during the CVD process. The appropriate supply of Te vapor to the Ag film influenced the stoichiometry of Ag-Te compounds, and the formation of stoichiometric Ag-Te compounds was well-explained by the phase diagram of the Ag-Te system. We found that Ag₂Te was grown in the liquid of Ag-Te under the Te-poor condition, while Ag₅Te₃ and Te were simultaneously solidified under the Te-rich condition. The high-temperature synthesis of Ag₂Te showed higher crystallinity and better stoichiometry than the low-temperature synthesis. This study demonstrates that Ag₂Te can be selectively synthesized by conventional CVD via delicate control over the phases of the complex Ag-Te system.