First-Principle Studies of Raman Spectroscopy and Vibrational and Thermal Properties of Materials

Diamond is an attractive semiconductor with properties such as high electron/hole mobility, thermal conductivity, and surface power density, which lend themselves well to radio frequency (RF) applications. In surface field effect transistors (SFET) of diamond, surface based vibrational properties are thought to be the limiting factors in device performance at higher temperatures and frequencies [1, 2]. However, there are limited studies on vibrational properties such as phonon dispersion and Raman spectra on these surfaces. Motivated by this, we aim to model the thermal and vibrational properties of diamond surfaces using a modified version of the VASP tool combined with Phonopy and ShengBTE. In this work, we have validated the predictability of the VASP tool by modeling and comparing vibrational properties of well-established bulk material systems (Si, GaN and Diamond) against the available experimental data. We have observed that the tool successfully predicts vibrational properties, within ±5% errors for the bulk Si, GaN, and Diamond material systems. Furthermore, to check the accuracy of the implemented model, we have also analyzed vibrational properties of the van der Waals (vdW) -layered materials such as MoS2 and MoO3. Additionally, we simulate the vibrational properties of the Diamond (100), (110), and (111) surfaces, and present a preliminary analysis of thermal properties of these surfaces compared to the bulk Diamond structure.