Temperature dependence of the local electronic properties of n-type GaN crystals by micro-Raman spectroscopy and dielectric dispersion at high temperatures

Abstract

Raman spectra for longitudinal optical phonon-plasmon coupled mode in n-type GaN crystals were measured from room temperature to 200 °C by micro-Raman spectroscopy. We calculated the electron density, electron mobility, and resistivity values of the sample by spectra analysis fitting of the imaginary part of the dielectric dispersion equation to this observed mode profiles using adjustable parameters in n-type GaN at high temperatures. The calculated values of the electron density, electron mobility, and resistivity reproduced those by Hall effect measurement. The results showed that the electron density values in n-type GaN tend to increase slightly with increasing temperature while the electric mobility decreases.