FAR-INFRARED OPTICAL-ABSORPTION STUDIES OF SINGLE-CRYSTAL RUS2-XSEX

The dichalcogenides single crystal RuS2-xSex have been studied by far- Infrared optical absorption measurements We measured these single crys tals in the spectra ranging from 100 - 700 cm(-1) over a temperature r ange from 80 to 300 K Those vibration modes of these crystals are clea rly shown temperature dependent behavior in far-infrared reflectance m easurements Also the temperature dependent vibration mode between thes e temperatures varies smoothly with the Se composition value (sic)x(si c) that clearly showed in the absorption spectra All these measured sp ectra indicate that the natures of phonons' behavior are similar to Ru S2 and RuSe2 in the limit of x values closing to 0 and 2. The main pea ks of phonon modes of RuS2-xSex are rich in around 207 to 416 cm(-1) a nd depend on intermediate compositions. All of these phonon modes are shown temperature dependent behavior These phonon modes have 1 - 9 cm( -1) shift between temperature at 80 - 300 K in its reflectance far-inf rared spectra. The phonon modes, carrier concentration, mobility, effe ctive mass as well as their dielectric behavior of these crystals will go further study.