Raman Spectroscopy as an alternative to approximate Debye temperature and lattice thermal conductivity
ABSTRACT :
In the case of modern nano-electronic devices, heat dissipation and power management are key issues for optimizing their performance. Materials with relati vely high thermal and decent electrical conductivity, like GaN, ZnO, and AIN, have been efficient in this regard. ZnO is widely used in optoelectronic applications such as diodes, sensors, solar cells, etc. It can be easily molded into several one or two-dimensional structures, and its thermal properties can be manipulated by doping of materials like Al and Mg, etc. Nanostructures experience phonon mode softening due to the large number of under-coordinated atoms. With minimal doping of 2 % - 3 %, thermal conductivity has been observed to decrease significantly, thus improving the figure of merit[1]. Here we propose an alternative method to calculate thermal conductivity and Debye temperature from temperature-dependent Raman Spectroscopy. The determination of Debye temperature from the temperature-dependent Raman Spectroscopy of ZnO will be discussed by considering the Bond-Order-Length-Strength [2] and Local Bond Averaging [3]. The calculation of the lattice thermal conductivity of the ZnO from the Debye temperature and Gruneissian parameters will be presented. Finally, the Debye temperature and lattice thermal conductivity obtained from the Raman thermometry will be compared with theoretical values calculated using the Phono3py under quasi-harmonic approximation.
ABOUT THE SPEAKER:
Biography of the Speaker :
PhD Scholar, Department of Physics, IIT Madras
Affiliation of the Speaker :
Guide: Dr. PRAHALLAD PADHAN