Triaxially strained suspended graphene for large-area pseudo-magnetic fields

• Main Authors: Luo, Manlin, Sun, Hao, Qi, Zhipeng, Lu, Kunze, Chen, Melvina, Kang, Dongho, Kim, Youngmin, Burt, Daniel, Yu, Xuechao, Wang, Chongwu, Kim, Young Duck, Wang, Hong, Wang, Qi Jie, Nam, Donguk
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Electrical and electronic engineering; Science::Physics; Crystallographic Directions; Raman Characterization
• Online Access: https://hdl.handle.net/10356/161852
• Institution: Nanyang Technological University

Strain-engineered graphene has garnered much attention recently owing to the possibilities of creating substantial energy gaps enabled by pseudo-magnetic fields (PMFs). While theoretical works proposed the possibility of creating large-area PMFs by straining monolayer graphene along three crystallographic directions, clear experimental demonstration of such promising devices remains elusive. Herein, we experimentally demonstrate a triaxially strained suspended graphene structure that has the potential to possess large-scale and quasi-uniform PMFs. Our structure employs uniquely designed metal electrodes that function both as stressors and metal contacts for current injection. Raman characterization and tight-binding simulations suggest the possibility of achieving PMFs over a micrometer-scale area. Current-voltage measurements confirm an efficient current injection into graphene, showing the potential of our devices for a new class of optoelectronic applications. We also theoretically propose a photonic crystal-based laser structure that obtains strongly localized optical fields overlapping with the spatial area under uniform PMFs, thus presenting a practical route toward the realization of graphene lasers.