Role of micro-Raman technique in material characterization of GaN wide bandgap semiconductor: Review

Abstract

Gallium Nitride (GaN) materials have unique electronic, optical, and mechanical properties that make them useful for various applications. However, these materials have complex structures and behavior, making it challenging to characterize them. Micro-Raman spectroscopy (MRS) is an appreciatively effective and adaptable method for analyzing the different properties of GaN materials, such as stress, strain, carrier concentration, and phonon lifetime. This review article provides an overview of the principles of MRS and its applications in GaN material characterization. The behavior of $E_2^H$ vibration modes of GaN material depends on the defects in the epilayer which alters the materials physical properties, such as stress and strain. The A₁(LO) vibration mode of longitudinal optical phonons provides information on electrical properties, such as carrier concentration and phonon lifetime. This review explains the MRS use in quantifying the physical and electrical properties of GaN materials over other characterization.