| Affiliation: | 1. School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW, 2052 Australia;2. Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, QLD, 4111 Australia;3. Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA, 90089 USA;4. Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072 Australia;5. Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin, 17104 Republic of Korea;6. Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052 Australia;7. School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, 4059 Australia;8. Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052 Australia
Tyree Institute of Health Engineering, University of New South Wales, Sydney, NSW, 2052 Australia;9. Department of Materials Science and Engineering, Department of Mechanical Engineering, Department of Biomedical Engineering, Departments of Electrical and Computer Engineering and Chemistry, and Department of Neurological Surgery, Northwestern University, Evanston, IL, 60208 USA |
| Abstract: | Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces. |
