Approaching the Glass Transition Temperature of GeTe by Crystallizing Ge15Te85. Issue 3 (24th November 2020)

• Record Type: Journal Article
• Authors: Pries, Julian; Yu, Yuan; Kerres, Peter; Häser, Maria; Steinberg, Simon; Gladisch, Fabian; Wei, Shuai; Lucas, Pierre; Wuttig, Matthias
• Other Names: Noé Pierre guestEditor.; Kooi Bart J. guestEditor.; Wuttig Matthias guestEditor.
• Is Part Of: Physica status solidi. Volume 15:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-24
• Subjects: crystallization kinetics -- glass transition -- metavalent bonding -- phase‐change materials -- undercooled liquids; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202000478
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : Like many phase‐change materials, GeTe crystallizes upon heating at a conventional rate before the calorimetric glass transition is reached. This has so far prevented an unambiguous determination of its glass transition temperature T g . Herein, a new approach is realized to estimate the glass transition temperature T g for GeTe through progressive crystallization of Ge15 Te85 . Selective crystallization of pure tellurium during sub‐ T g annealing leads to a gradual change in the composition of the amorphous surrounding toward that of GeTe. This gives rise to a new endotherm whose onset temperature gradually approaches the T g of GeTe. Abstract : When the eutectic composition Ge15 Te85 crystallizes, it transforms into tellurium and GeTe during two distinct crystallization events. As tellurium crystallizes first, the composition of the remaining amorphous material changes toward that of GeTe. During that shift in composition, an endotherm of a glass transition develops, whose onset approaches the glass transition temperature T g of GeTe.