Graphene nanoribbons(GNRs)are regarded as an ideal candidate for beyond-silicon electronics.However,synthesis of aligned GNR arrays on insulating substrates with high efficiency is challenging.In this work,we develop ...Graphene nanoribbons(GNRs)are regarded as an ideal candidate for beyond-silicon electronics.However,synthesis of aligned GNR arrays on insulating substrates with high efficiency is challenging.In this work,we develop a facile strategy,involving KOH pre-treatment and high-temperature annealing,to construct parallel steps on the two-fold symmetry a-plane sapphire substrate.Horizontal GNRs as narrow as 15.1 nm with global alignment across a region of 20 mm^(2)are then grown on the step edgeenriched substrate through plasma enhanced chemical vapor deposition(PECVD)method.GNRs align well along the atomic steps on sapphire([■]direction)with their widths and densities swiftly adjustable by step morphology modification on substrate surface.A step-edge confined growth mechanism is proposed,attributing the constraint on the nanoribbon broadening to a relatively low growth temperature in PECVD,which restrains the activation energy to suppress GNRs across step edges on sapphire and prevents detrimental nanoribbon widening.The results provide a new perspective for scalable synthesizing well aligned nanoribbons of other two-dimensional materials.展开更多
基金This work was financially supported by the Ministry of Science and Technology of China(Nos.2016YFA0200100 and 2018YFA0703502)the National Natural Science Foundation of China(Nos.52021006,51720105003,21790052,and 21974004)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36030100)the Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXTD-202001).
文摘Graphene nanoribbons(GNRs)are regarded as an ideal candidate for beyond-silicon electronics.However,synthesis of aligned GNR arrays on insulating substrates with high efficiency is challenging.In this work,we develop a facile strategy,involving KOH pre-treatment and high-temperature annealing,to construct parallel steps on the two-fold symmetry a-plane sapphire substrate.Horizontal GNRs as narrow as 15.1 nm with global alignment across a region of 20 mm^(2)are then grown on the step edgeenriched substrate through plasma enhanced chemical vapor deposition(PECVD)method.GNRs align well along the atomic steps on sapphire([■]direction)with their widths and densities swiftly adjustable by step morphology modification on substrate surface.A step-edge confined growth mechanism is proposed,attributing the constraint on the nanoribbon broadening to a relatively low growth temperature in PECVD,which restrains the activation energy to suppress GNRs across step edges on sapphire and prevents detrimental nanoribbon widening.The results provide a new perspective for scalable synthesizing well aligned nanoribbons of other two-dimensional materials.
