Optical properties and electronic energy-band structure of CdIn_2Te_4

摘要

Optical properties of a defect-chalcopyrite-type semiconductor CdIn_2Te_4 have been studied by optical absorption, spectroscopic ellipsometry (SE), and ther-moreflectance (TR) measurements. Optical absorption measurements suggest that CdIn_2Te_4 is a direct-gap semiconductor having the bandgap of ～1.22 eV at 300 K. The complex dielectric-function spectra, ε(E) = ε_1(E) + iε_2(E), measured by SE reveal distinct structures at energies of the critical points in the Brillouin zone. TR spectroscopy facilitates the precision determination of the critical point energies. By performing the band-structure calculation, such critical points are successfully assigned to specific points in the Brillouin zone.