One-Dimensional Phase-Change Nanostructure:  Germanium Telluride Nanowire

Abstract

High-quality nanowires of germanium telluride (GeTe), a one-dimensional chalcogenide phase-change nanostructure, were synthesized via thermal evaporation method under vapor−liquid−solid mechanism. The physical morphology, chemical composition, and crystal structure of the as-synthesized GeTe nanowires were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy. Through real-time TEM imaging of nanowire sample heated in an incrementally controllable heating system, the melting point of a single crystalline GeTe nanowire (∼40−80 nm diameter) is found to be significantly lower than that of its bulk counterpart (46% reduction, from 725 to 390 °C). The significant reduction in melting point makes one-dimensional phase-change chalcogenide nanowire a potential material for application in low-power high-density resistive switching nonvolatile data storage in which the thermal energy for material phase transition would be significantly reduced.

Facile fabrication of silicon and aluminum oxide nanotubes using antimony telluride nanowires as templates

“…3 revealed that core STNWs started to melt at the one third temperature of the melting point of bulk ST (621 1C) [17]. It is well known that the melting point of low-dimensional materials is lower than that of bulk materials due to the size-effect [18,19]. This is the first observation of the lower melting temperature of STNWs, and indicates that they might be used in fabricating SONTs at low temperature.…”

Transmission Electron Microscopy on Memristive Devices: An Overview

“…entire networks of switchable structures are used. They can frequently be deposited right on top of electron transparent membranes as parts of TEM sample grids without any need for careful placement (Avizienis et al, 2012;Liang et al, 2014;Sun et al, 2007). Alternatively, the nanowires can be randomly dispersed and the electrodes are deposited and shaped in a later stage with lithographic means (Chiang et al, 2011).…”

“…In terms of TEM analysis these devices are advantageous because they forestall the need for complicated and time-consuming crosssectional specimen preparation if deposited directly onto electron transparent membranes. Horizontal memristive devices have been realized with switching nano-structures containing Ag wires (Avizienis et al, 2012), CuO nanowires (Fan et al, 2013;Liang et al, 2014), ZnO nanowires (Chiang et al, 2011), TiO 2 (Lin et al, 2016), Cu 2 S nanowires (Liu et al, 2015), GeTe nanowires (Sun et al, 2007), and Ge/Si nanowires (Yan et al, 2011). The large variety of material systems analyzed underlines the flexibility and relative ease with which such investigations can be conducted.…”

A novel top-down fabrication process for Ge<inf>2</inf>Sb<inf>2</inf>Te<inf>5</inf> phase change material nanowires

“…It provides the potential for high scaled phase change memory devices and multilevel memory applications. Single-crystal nanowires based on different phase change materials such as GeTe [2][3][4][5][6],GeSb [7], Ge 2 Sb 2 Te 5 [8][9][10][11], Ge 1 Sb 2 Te 4 [12] and In 2 Se 3 [13] have been previously synthesized and demonstrated a nano-second level switching time at very low powers, suggesting that the nanowires could be ideal for data storage devices.…”