When excited optically, some substances give forth light on their own. Excitation energy and intensity are utilized to probe sample areas and excitation concentrations. Multiple qualities of a material may be described via PL. For the purpose of electrical characterization, PL spectroscopy may selectively and sensitively investigate individual electronic states. Emission spectra are useful for characterizing alloys in terms of their degree of disorder, interface roughness, surface, and interface impurity. The strength of the PL signal provides information about the surface and interface. The lifespan of the nonequilibrium interface and bulk state during pulsed stimulation is determined by the strength of the transient PL. By manipulating the PL intensity while the sample is biased, the surface electric field may be mapped. PL intensity is temperature-dependent due to thermally induced processes. Analyzing PL without causing damage. There is minimal sample manipulation and no controlled environments required for this method. Optical excitation of the sample eliminates the need for low-permeability materials. In addition, timeresolved PL.