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

Journal Article · Fri Jan 15 00:00:00 EST 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4941072· OSTI ID:22492401

Kabuyanagi, Shoichi; Nishimura, Tomonori; Yajima, Takeaki; Toriumi, Akira ^[1]

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1. Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656 (Japan)

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.

• OSTI ID: 22492401
• Journal Information: AIP Advances, Vol. 6, Issue 1; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMS
CHARGE CARRIERS
COVALENCE
DIELECTRIC MATERIALS
DOPED MATERIALS
FILMS
GERMANIUM
HOLES
MODIFICATIONS
PHONONS
RAMAN SPECTROSCOPY
ZONES