Graphene-induced lasing mode tailoring in GaN floating microring cavity

Abstract

Due to its unique properties, such as high electron and thermal conductivities, graphene has attracted much attention, especially in its applications to optoelectronic devices. Herein, graphene is used in the tailoring of the lasing mode from a floated GaN microring cavity. The lasing performances of the GaN cavities are investigated, including its lasing intensity, full width at half maximum (FWHM) and mode properties for samples with or without the presence of graphene. We show that clear side-mode suppression, and an improvement in the photoluminescence (PL), is obtained for samples containing graphene. For samples covered with graphene, the threshold values are reduced by half and the PL intensity is enhanced by over 20 times. Based on observations of the PL evolution in terms of spontaneous emission, the side-mode suppression phenomenon can be attributed to electrons transfer induced PL modulation. Our work reveals a promising strategy for fabricating high-performance optoelectronic device.