Experimental evidence of zone-center optical phonon softening by accumulating holes in thin Ge

Shoichi Kabuyanagi, Tomonori Nishimura, Takeaki Yajima, Akira Toriumi

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5 Citations (Scopus)

Abstract

We discuss the impact of free carriers on the zone-center optical phonon frequency in germanium (Ge). By taking advantage of the Ge-on-insulator structure, we measured the Raman spectroscopy by applying back-gate bias. Phonon softening by accumulating holes in Ge film was clearly observed. This fact strongly suggests that the phonon softening in heavily-doped Ge is mainly attributed to the free carrier effect rather than the dopant atom counterpart. Furthermore, we propose that the free carrier effect on phonon softening is simply understandable from the viewpoint of covalent bonding modification by free carriers.

Original languageEnglish
Article number015114
JournalAIP Advances
Volume6
Issue number1
DOIs
Publication statusPublished - Jan 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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