| 초록 |
This seminar introduces the recent progress of laser material interactions for flexible electronic applications. Laser is important for future flexible electronics since it can adopt high temperature process on plastics, which is essential for high performance electronics. The first part will discuss the flexible transparent conducting electrodes (FTCEs) of Ag nanowires (Ag NWs) using flash light-material interactions. Ag NWs have received huge attention for future FTCEs, however, they have drawbacks such as high wire-to-wire contact resistance and poor adhesion to substrates. Our flash-induced Ag NWs have low sheet resistance (~5 Ω/sq-1), high transmittance (90 % at λ = 550 nm), and strong adhesion to plastic substrates (interfacial energy of 30.7 J∙m-2). UV spectrum of a flash lamp enables the localized heat energy for the junction annealing, while the near-infrared (NIR) melted the interface between the Ag NWs and plastic substrate, enhancing the adhesion force. The second part will introduce the laser material interaction for two-dimensional nano-materials. A single-pulse irradiation of excimer laser melts SiC leads to the separation of a liquid SiC layer into graphitic carbon domains (2.5 nm thick) on top surface and a silicon layer (about 5 nm) below carbon layer. Additional pulses cause the sublimation of the separated silicon, while the disordered carbon layer is transformed into a multilayer graphene. This technology is powerful tool for making new synthesis method of two dimensional materials. The third part will discuss self-powered flexible electronics via inorganic based laser lift off (ILLO). Flexible large scale integration (LSI) and piezoelectric energy harvester was transferred from bulk substrates to flexible substrates by inorganic based laser liftoff (ILLO) for not only data processing/storage but also self-powered biomedical devices. |
