Optical properties and electronic band structure ofZnIn2Te4

Abstract

Optical properties of the defect-chalcopyrite-type semiconductor ${\mathrm{ZnIn}}_{2}{\mathrm{Te}}_{4}$ have been studied by optical absorption, spectroscopic ellipsometry, and x-ray photoelectron spectroscopy. Optical absorption measurements suggest that ${\mathrm{ZnIn}}_{2}{\mathrm{Te}}_{4}$ is a direct-gap semiconductor having a band gap of \ensuremath{\sim}1.40 eV. The complex dielectric-function spectra $\ensuremath{\varepsilon}(E)={\ensuremath{\varepsilon}}_{1}(E)+i{\ensuremath{\varepsilon}}_{2}(E),$ measured by spectroscopic ellipsometry, reveal distinct structures at energies of the critical points in the Brillouin zone. Analysis of the numerically derived $\ensuremath{\varepsilon}(E)$ spectra facilitates the precise determination of the critical point parameters (energy position, strength, and broadening). By performing the band-structure calculation, these critical points are successfully assigned to specific points in the Brillouin zone. The measured x-ray photoelectron spectrum is also presented along with the density-of-states $N(E)$ calculation.