Graphene-induced lasing mode tailoring in GaN floating microring cavity

¹ Peter Grünberg Research Centre, College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications - Nanjing 210003, China
² State Key Laboratory of Bioelectronics, Southeast University - Nanjing 210096, China
³ College of Science, Nanjing University of Aeronautics and Astronautics - Nanjing 211106, China

^(a) zhugangyi@njupt.edu.cn (corresponding author)
^(b) wangyj@njupt.edu.cn

Received: 24 June 2021
Accepted: 7 September 2021

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.