Tailoring Crystallization Kinetics of Chalcogenides for Photonic Applications
Maximilian J. Müller, Aakash Yadav, Christoph Persch, Sophia Wahl, Felix Hoff, Matthias Wuttig
Abstract
Abstract Chalcogenides possess interesting optical properties, which are attractive for a variety of applications such as data storage, neuromorphic computing, and photonic switches. Lately a group of covalently bonded chalcogenides including Sb 2 Se 3 and Sb 2 S 3 has moved into the focus of interest for such photonic applications, where high optical contrast as well as reliable and fast switching is of crucial importance. Here, these properties of Sb 2 Se 3 are examined and compared with typical phase change materials such as GeSb 2 Te 4 and Ge 2 Sb 2 Te 5 . Sb 2 Se 3 is favorable for many photonic applications due to its larger band gap, yet, the maximum optical contrast achievable is smaller than for GeTe and Ge 2 Sb 2 Te 5 . Furthermore, crystallization needs significantly longer and exhibits a distinctively wider stochastic distribution of reflectances after crystallization, which provides challenges for the usage in photonic applications. At the same time, the glassy/amorphous state of Sb 2 Se 3 is more stable. These differences can be attributed to differences in bonding of the crystalline state, which is more covalent for Sb 2 Se 3 . A quantum‐chemical map can help to understand and explain these trends and facilitates the design of tailored materials for photonic applications.