title: Step-Controllable Electric-Field-Assisted Nanoimprint Lithography for Uneven Large-Area Substrates.
abstract: Large-area nanostructures are widely used in various fields, but fabrication on large-area uneven substrates poses a significant challenge. This study demonstrates a step-controllable electric-field-assisted nanoimprint lithography (e-NIL) method that can achieve conformal contact with uneven substrates for high fidelity nanostructuring. Experiments are used to demonstrate the method where a substrate coated with liquid resist is brought into contact with a flexible template driven by the applied electric field. Theoretical analysis based on the elasticity theory and electro-hydrodynamic theory is carried out. Effective voltage range and the saturation voltage are also discussed. A step-controllable release of flexible template is proposed and demonstrated to ensure the continuous contact between the template and an uneven substrate. This prevents formation of air traps and allows large area conformal contact to be achieved. A combination of Vacuum-electric field assisted step-controllable e-NIL is implemented in the developed prototype. Finally, photonic crystal nanostructures are successfully fabricated on a 4 in., 158 μm bow gallium nitride light-emitting diode epitaxial wafer using the proposed method, which enhance the light extraction property.
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.|Shaanxi Province Key Laboratory of Thin Film Technology and Optical Test, Xi'an Technological University , Xi'an, Shaanxi 710032, China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Wang
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.
authors.forename: Jinyou
authors.initials: J
authors.lastname: Shao
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.
authors.forename: Hongmiao
authors.initials: H
authors.lastname: Tian
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.
authors.forename: Xiangming
authors.initials: X
authors.lastname: Li
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China.|Department of Mechanical Engineering, College of Engineering and Computer Science, University of Michigan-Dearborn , Dearborn, Michigan 48128, United States.
authors.forename: Ben Q
authors.initials: BQ
authors.lastname: Li
keywords: LED; electric field assisted; nanoimprint lithography; nanopatterning; photonic crystal