Controllable crystal growth and fast reversible crystallization-to-amorphization in Sb2Te-TiO2 films

Guoxiang Wang; Chao Li; Daotian Shi; Qiuhua Nie; Hui Wang; Xiang Shen; Yegang Lu

doi:10.1038/srep46279

Controllable crystal growth and fast reversible crystallization-to-amorphization in Sb₂Te-TiO₂ films

Sci Rep. 2017 Apr 11:7:46279. doi: 10.1038/srep46279.

Authors

Guoxiang Wang^{1

2}, Chao Li^{1

2}, Daotian Shi^{1

2}, Qiuhua Nie^{1

2}, Hui Wang^{1

2}, Xiang Shen^{1

2}, Yegang Lu^{1

2}

Affiliations

¹ Laboratory of Infrared Material and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
² Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, 315211, China.

Abstract

The structure evolution and crystallization processes of Sb₂Te-TiO₂ films have been investigated. The Sb₂Te-rich nanocrystals, surrounded by TiO₂ amorphous phases, are observed in the annealed Sb₂Te-TiO₂ composite films. The segregated domains exhibit obvious chalcogenide/TiO_x interfaces, which elevate crystallization temperature, impede the grain growth and increase crystalline resistance. Compared with that in conventional Ge₂Sb₂Te₅ film, the shorter time for onset crystallization (25 ns) and amorphization (100 ns) has been achieved in as-deposited (Sb₂Te)_94.7(TiO₂)_5.3 film under 60 mW laser irradiation. The corresponding recrystallization and re-amorphization can also be realized in the film. From Johnson-Mehl-Avrami (JMA) analysis, it is further found that the one-dimensional grain growth with controlled interface is dominant for the film during the fast phase-change process. Therefore, (Sb₂Te)_94.7(TiO₂)_5.3 film with improved crystallization mechanism is promising for high-stable and fast-speed memory applications.

Publication types

Research Support, Non-U.S. Gov't