Stacking Polymorphism in PtSe2 Drastically Affects Its Electromechanical Properties. Issue 22 (2nd June 2022) - Kempt, Roman
Abstract: PtSe2 is one of the most promising materials for the next generation of piezoresistive sensors. However, the large‐scale synthesis of homogeneous thin films with reproducible electromechanical properties is challenging due to polycrystallinity. It is shown that stacking phases other than the 1T phase become thermodynamically available at elevated temperatures that are common during synthesis. It is shown that these phases can make up a significant fraction in a polycrystalline thin film and discuss methods to characterize them, including their Seebeck coefficients. Lastly, their gauge factors, which vary strongly and heavily impact the performance of a nanoelectromechanical device are estimated. Abstract : Order matters: In this study, the authors show that stacking disorder occurs at temperatures between 400 and 500 °C in PtSe2, which is a candidate material for next‐generation piezoresistive sensors. However, some stacking phases might be beneficial due to their higher gauge factors, albeit their characterization is challenging.