Variations in the intensity of lasing in vertical ZnO nanorods with polarization of optical excitation
Résumé
The polarization dependences of emission and optical excitation of an array of vertical ZnO semiconductor nanorods synthesized on the Si (100) substrate are analyzed. Because of the surface charge induced due to the difference between the permittivities of the nanorods and their surroundings, the absorption coefficient and the emission coefficient are different for the light polarized in parallel or perpendicularly to the axes of the nanorods. As a result, the intensity and spectra of luminescence in the array of parallel nanorods are highly sensitive to the polarization of excitation. Study of the behavior of the laser spectrum with the polarization of excitation shows good agreement of the data with the theory of induced charge. The mechanism of lasing is related to the formation of paths of light due to multiple scattering in the array of vertically oriented ZnO nanorods.