1. Probing the exciton-phonon coupling strengths of O-polar and Zn-polar ZnO wafer using hard X-ray excited optical luminescence
- Author
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Bi-Hsuan Lin, Shao-Chin Tseng, Chien-Yu Lee, Huang-Yeh Chen, Mau-Tsu Tang, Gung-Chian Yin, Wen-Feng Hsieh, Jian-Xing Wu, Bo-Yi Chen, and Shih-Hung Chang
- Subjects
010302 applied physics ,Materials science ,Photoluminescence ,Physics and Astronomy (miscellaneous) ,Phonon ,Exciton ,Binding energy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Condensed Matter::Materials Science ,Excited state ,0103 physical sciences ,Atomic physics ,0210 nano-technology ,Luminescence ,Spectroscopy ,Single crystal - Abstract
The temperature-dependent hard X-ray excited optical luminescence (XEOL) spectroscopy was used to study the optical properties of O and Zn polarity of a c-plane single crystal ZnO wafer. By analyzing the XEOL and XRD, we found an unprecedented blue shift of the free exciton transition with increasing the excited carrier density as tuning the X-ray energy across the Zn K-edge, and the O-polar face possesses better crystal structure than the Zn-polar one. This spectral blue shift is attributed to the Coulomb screening of the spontaneous polarization by the excited free carriers that result in decreasing the exciton-phonon Frohlich interaction to reduce exciton binding energy.
- Published
- 2016