Publication details
Dielectric function and band gap determination of single crystal CuFeS2 using FTIR-VIS-UV spectroscopic ellipsometry
| Authors | |
|---|---|
| Year of publication | 2023 |
| Type | Article in Periodical |
| Magazine / Source | Optical Materials Express |
| MU Faculty or unit | |
| Citation | |
| Web | https://opg.optica.org/ome/fulltext.cfm?uri=ome-13-7-2020&id=532139 |
| Doi | http://dx.doi.org/10.1364/OME.493426 |
| Keywords | ELECTRONIC; STRUCTUREOPTICAL; PROPERTIESSPIN; WAVES CHALCOPYRITE PHONONS GROWTH |
| Description | 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 & PLUSMN; 2 x 1019 & SIM;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. |