Understanding the crystallization behavior of as-deposited Ti-Sb-Te alloys through real-time radial distribution functions

Phase change materials, successfully used in optical data-storage and non-volatile electronic memory, are well-known for their ultrafast crystallization speed. However, the fundamental understanding of their crystallization behavior, especially the nucleation process, is limited by present experimen...

Full description

Saved in:
Bibliographic Details
Published in:Nanoscale 2015-06, Vol.7 (21), p.9935-9944
Main Authors: Zhu, Min, Xia, Mengjiao, Song, Zhitang, Cheng, Yan, Wu, Liangcai, Rao, Feng, Song, Sannian, Wang, Miao, Lu, Yegang, Feng, Songlin
Format: Article
Language:English
Subjects:
Alloys
Chemical bonds
Crystallization
Nucleation
Nuclei
Radial distribution
Real time
Titanium
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Phase change materials, successfully used in optical data-storage and non-volatile electronic memory, are well-known for their ultrafast crystallization speed. However, the fundamental understanding of their crystallization behavior, especially the nucleation process, is limited by present experimental techniques. Here, real-time radial distribution functions (RDFs), derived from the selected area electron diffractions, are employed as structural probes to comprehensively study both nucleation and subsequent growth stages of Ti-doped Sb2Te3 (TST) materials in the electron-irradiation crystallization process. It can be found that the incorporation of Ti atoms in Sb2Te3 forms wrong bonds such as Ti-Te, Ti-Sb, breaks the originally ordered atomic arrangement and diminishes the initial nucleus size of the as-deposited films, which results in better thermal stability. But these nuclei hardly grow until their sizes exceed a critical value, and then a rapid growth period starts. This means that an extended nucleation time is required to form the supercritical nuclei of TST alloys with higher concentration. Also, the increasing formation of four-membered rings, which served as nucleation sites, after doping excessive Ti is responsible for the change of the crystallization behavior from growth-dominated to nucleation-dominated.
ISSN:2040-3364
2040-3372
DOI:10.1039/c4nr07408d