Photoreflectance Spectroscopy of ZnO for Ordinary and Extraordinary Rays

概要

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Photoreflectance (PR) measurements have been carried out to determine the fundamental-absorption-edge ($E_{0})$ structure of ZnO for light polarization $\mathbf{E}$ perpendicular ($\mathbf{E} \perp{c}$) and parallel to the $c$-axis ($\mathbf{E} \parallel{c}$) at temperatures $T$ between 15 and 300 K. The measured PR spectra revealed distinct structures at $\sim$3.3–3.5 eV. These structures could be successfully interpreted using the three-dimensional (3D) excitonic plus one-electron line shapes over the entire temperature range. The temperature dependence of the 3D critical-point and excitonic parameters (energy, amplitude and broadening parameter) has also been determined and analyzed using the Varshni equation and an analytical four-parameter expression recently developed for the explanation of the band-gap shrinkage effect in semiconductors. The 3D-exciton binding energies were determined to be 65 ($A$), 68 ($B$) and 63 meV ($C$), respectively.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2003-09-15