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

Research Projects

Organizational Units

Organizational Unit
Department of Electrical & Electronics Engineering
Department of Electrical and Electronics Engineering (EE) offers solid graduate education and research program. Our Department is known for its student-centered and practice-oriented education. We are devoted to provide an exceptional educational experience to our students and prepare them for the highest personal and professional accomplishments. The advanced teaching and research laboratories are designed to educate the future workforce and meet the challenges of current technologies. The faculty's research activities are high voltage, electrical machinery, power systems, signal and image processing and photonics. Our students have exciting opportunities to participate in our department's research projects as well as in various activities sponsored by TUBİTAK, and other professional societies. European Remote Radio Laboratory project, which provides internet-access to our laboratories, has been accomplished under the leadership of our department with contributions from several European institutions.

Journal Issue

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

Start Page

End Page

Collections