| Autor: |
Shigetaka Nomura, Shigetaka Nomura, Shin-ichi Ouchi, Shin-ichi Ouchi, Saburo Endo, Saburo Endo |
| Zdroj: |
Japanese Journal of Applied Physics; August 1997, Vol. 36 Issue: 8 pL1075-L1075, 1p |
| Abstrakt: |
Raman spectra of ordered vacancy compounds (OVC) of CuIn2Se3.5and CuIn3Se5have been measured at room temperature. Similar nonpolarized Raman spectra are obtained for CuIn2Se3.5and CuIn3Se5. However, polarized Raman spectra are not available for CuIn3Se5because of its unfavorable crystallinity. A signal at 154 cm-1is assigned to be ?1mode of D2dsymmetry, originating from the vibration of selenium atoms in the x-y(a-axes) plane. This signal corresponds to the signal at 178 cm-1for CuInSe2of chalcopyrite-type in the Cu-In-Se system. The lowering of ?1mode frequency for the defect structure is attributed to looser-bound selenium atoms on account of vacancies in the cation sites. Signals assigned as ?3mode are unexpectedly observed in the geometries allowing the longitudinal optical (LO) modes of ?4and ?5symmetries. The respective mode peaks are found to be more dispersive in frequency for CuIn2Se3.5than for CuInSe2. |
| Databáze: |
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