Synthesis of Macroscopic Single Crystals of Ge2Sb2Te5via Single-Shot Femtosecond Optical Excitation

Marc Zajac, Aditya Sood, Taeho R. Kim, Mianzhen Mo, Michael Kozina, Suji Park, Xiaozhe Shen, Burak Guzelturk, Ming Fu Lin, Jie Yang, Stephen Weathersby, Xijie Wang, Aaron M. Lindenberg

Research output: Contribution to journalArticlepeer-review


Using in situ electron diffraction techniques, we demonstrate that femtosecond optical excitation above a threshold fluence of the amorphous, as-deposited, phase change material Ge2Sb2Te5 creates large, 100 μm scale single crystals. This is 2 orders of magnitude larger than previously reported grains synthesized via photoexcitation. Transmission electron microscopy shows that these large crystals are dewetted regions with a face-centered cubic structure. Energy-dispersive X-ray spectroscopy indicates that the crystals have the same composition as the initial amorphous phase. We present a theoretical model which shows that this arises from a crossover from a nucleation-dominated crystallization regime to a growth-dominated crystallization regime, and we show that the measured grain size is consistent with Johnson-Mehl-Avrami-Kolmogorov (JMAK) crystallization theory for temperatures near the melting temperature. The ability to grow macroscopic single crystals from an amorphous material, and on arbitrary amorphous substrates, opens up a large area of potential applications, as well as new opportunities for tuning the nucleation, growth, and switching characteristics of phase-change materials.

Original languageEnglish (US)
Pages (from-to)6660-6667
Number of pages8
JournalCrystal Growth and Design
Issue number10
StatePublished - Oct 7 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics


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