Affiliation:
1. Norwegian University of Science and Technology (NTNU)
2. Masaryk University, and Central European Institute of Technology, Brno University of Technology
Abstract
Spectroscopic ellipsometry measurements were performed on antiferromagnetic semiconductor CuFeS2 grown via molecular beam epitaxy. UV/Visible and IR ellipsometry data was merged and modeled to derive the dielectric function of CuFeS2 from 30 meV to 4.5 eV. The CuFeS2 samples were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and cross-section scanning electron microscopy (SEM) which gave the crystal quality, surface roughness and sample film thickness. A critical point analysis revealed a direct band gap of 0.76 eV, while modeling gives a carrier concentration of 8 ± 2 × 1019~cm−3 and an estimate of the indirect band gap of 0.5 eV. Optically active infrared phonons were observed at 319 cm−1 and 350 cm−1 with significant Raman active modes at 85.8 cm−1, 265 cm−1, 288 cm−1, 318 cm−1 and 377 cm−1. The fitted optical constants were then used to characterize the crystal quality and spatial uniformity.
Subject
Electronic, Optical and Magnetic Materials