Activation energy of metastable amorphous Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> from room temperature to melt
No Thumbnail Available
Date
2018
Authors
Bakan, Gökhan
Scoggin, Jake
Dirisaglik, Faruk
Adnane, Lhacene
Cywar, Adam
Bakan, Gokhan
Gokirmak, Ali
Journal Title
Journal ISSN
Volume Title
Publisher
Amer inst Physics
Open Access Color
OpenAIRE Downloads
OpenAIRE Views
Abstract
Resistivity of metastable amorphous Ge2Sb2Te5 (GST) measured at device level show an exponential decline with temperature matching with the steady-state thin-film resistivity measured at 858 K (melting temperature). This suggests that the free carrier activation mechanisms form a continuum in a large temperature scale (300 K - 858 K) and the metastable amorphous phase can be treated as a supercooled liquid. The effective activation energy calculated using the resistivity versus temperature data follow a parabolic behavior, with a room temperature value of 333 meV, peaking to similar to 377 meV at similar to 465 K and reaching zero at similar to 930 K, using a reference activation energy of 111 meV (3k(B)T/2) at melt. Amorphous GST is expected to behave as a p-type semiconductor at T-melt similar to 858 K and transitions from the semiconducting-liquid phase to the metallic-liquid phase at similar to 930 K at equilibrium. The simultaneous Seebeck (S) and resistivity versus temperature measurements of amorphous-fcc mixed-phase GST thin-films show linear S-T trends that meet S = 0 at 0 K, consistent with degenerate semiconductors, and the dS/dT and room temperature activation energy show a linear correlation. The single-crystal fcc is calculated to have dS/dT = 0.153 mu V/K-2 for an activation energy of zero and a Fermi level 0.16 eV below the valance band edge. (C) 2018 Author(s).
Description
Silva, Helena/0000-0001-6356-5402; Scogin, Jake/0000-0003-4465-7701; Adnane, Lhacene/0000-0002-7925-4534; Gokirmak, Ali/0000-0001-5940-899X; Muneer, Sadid/0000-0002-4166-2807; Bakan, Gokhan/0000-0001-8335-2439
Keywords
[No Keyword Available]
Turkish CoHE Thesis Center URL
Fields of Science
Citation
10
WoS Q
Q4
Scopus Q
Q2
Source
Volume
8
Issue
6