| Original Articles |
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Phase Transition and Temperature Dependence of the A1 Low-Frequency Exciton Band Parameters in Quaternary Compound Rb0.5Cs0.5Ag4I5 Thin Films |
| SUN Jia-Lin;TIAN Guang-Yan;CAO Yang;SHI Shuo;TAN Xiao-Jing;CHEN Tao |
| Key Laboratory of Atomic and Molecular Nanosciences of Education Ministry and Department of Physics, Tsinghua University, Beijing 100084
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| Cite this article: |
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SUN Jia-Lin, TIAN Guang-Yan, CAO Yang et al 2002 Chin. Phys. Lett. 19 1326-1328 |
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Abstract The absorption spectra of the A1 low-frequency exciton band in quaternary compound Rb0.5Cs0.5Ag4I5 thin films have been measured by an UV-2100 spectrophotometer at the temperature (T) range from 78 to 289 K. The measurements at intermediate temperatures are performed within an interval of photon energies from 3.44 to 3.70 eV. The spectra have been computer-processed to separate the A1 band from the interband absorption edges, and to determine their parameters: the spectral peak position (Em), the half-width (G) of the exciton band, and the Gaussian shape ratio in the spectrum. The results show that at T < 107 K, dEm/dT = -6.34 x 10-4 eV.K-1, dG/dT = 3.04 x 10-4 eV.K-1; at T > 107 K, dEm/dT = -3.01 x 10-4 eV.K-1, dG/dT = 5.47 x 10-4 eV.K-1. It is emphasized that the phase transition γ → β in this material is carried out at temperature 107 K.
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| Keywords:
71.35.Cc
68.55.Nq
74.70.Dd
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Published: 01 September 2002
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| PACS: |
71.35.Cc
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(Intrinsic properties of excitons; optical absorption spectra)
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68.55.Nq
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(Composition and phase identification)
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74.70.Dd
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(Ternary, quaternary, and multinary compounds)
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