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Urbach tail in the absorption spectra of 2H-WSe2layered crystals

✍ Scribed by Hu, S. Y. ;Lee, Y. C. ;Shen, J. L. ;Chen, K. W. ;Huang, Y. S.

Publisher
John Wiley and Sons
Year
2007
Tongue
English
Weight
391 KB
Volume
204
Category
Article
ISSN
0031-8965

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✦ Synopsis

Abstract

Urbach's rule and steepness parameter of 2H‐WSe~2~ layered crystals have been studied via the absorption spectra from the photoconductivity (PC) measurements in the temperature range of 15–300 K. From the analysis of the temperature‐dependent band gap with Varshni semi‐empirical equation, the Debye temperature was estimated as 160 K while the Einstein temperature was around 125 K from the Einstein oscillator model. The effective phonon energy was estimated successfully from the temperature dependence of the Urbach energy extracted from the PC spectra and the value was found out to be well correlated to the active E~1g~ mode observed in the Raman spectra of 2H‐WSe~2~. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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