an NSF-sponsored center for nanoscale science and engineering Testbeds and Applications Goals Materials and Device Designs for Printed Displays, Lighting & Energy Mapping to Center’s Objectives Fundamental Questions/Challenges Research Plan Research Results & Broader Impact Future Efforts (Image from Choquette group website, UIUC) • Printable, microscale inorganic light emitting diode (LED) lighting elements. • Passive-/active-matrix micro-LED pixel arrays on low-cost, transparent, flexible, and/or stretchable substrates. Fabricate printable, micro/nanoscale, lighting elements. Develop printing technologies for assembly on arbitrary substrates. Manufacture lighting/display systems with superior mechanical and optical characteristics. Active matrix displays “Can micromanipulation strategies enable practical manufacturing of high-resolution, large-area inorganic lighting/display systems?” Micromanipulation: Transfer printing Micromanipulation: Transfer printing Interaction with Other Projects Build micro-LED lighting and passive matrix displays on low-cost, flexible, and/or stretchable substrates. Fabricate printable micro-LED devices from epilayers on semiconductor wafers. Develop reliable, scaleable micro-assembly technology based on nano-CEMMS transfer printing. Manufacture high-resolution micro-LED lighting and displays: transparent, flexible, and/or stretchable. Development of inorganic optical sources: With Choquette and Li groups Process integration platforms: Transfer printing: With Ferreira group Flexible passive matrix display with transparency Inorganic micro Inorganic micro- LED operation LED operation Printable lasers Applied Voltage (V) -1 0 1 2 3 4 Current (A) -0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 4 mm Anode line Anode line Data line Data line Gate line Gate line ILED ILED TFT TFT Collaboration : Ferreira, Choquette, Li groups • High efficiency & brightness • Rugged; robust operation • Massively parallel assembly • Control micro/nanoscale objects 0.2 mm 2 mm 1 cm Foldable lighting system Epilayer design for printable LEDs 2 μm 1. GaAs:C, 5 nm 2. Al 0.45 Ga 0.55 As:C, 800 nm 3. Al 0.5 In 0.5 P:Zn, 200 nm 4-12. Active region 13. Al 0.5 In 0.5 P:Si, 200 nm 14. Al 0.45 Ga 0.55 As:Si, 800 nm 15. GaAs:Si, 500 nm 16. Al 0.96 Ga 0.04 As, 1500 nm. 17. GaAs, 1500 nm 18. Al 0.96 Ga 0.04 As, 500 nm 19. GaAs substrate Transfer print n times. Lift off LEDs onto the surface of a stamp. Stamp Micro-LED Printed LED system 50 μm 0.7 mm Donor wafer Stretchable passive matrix display & Strechable lighting system 4.4 Sacrificial layer iLED (2.5 μ μ μm) 2 mm 5 mm 3 mm 3 mm 500 μm 200 μm 5 mm 5 mm 50 μm 1 mm 1 mm 2 mm PDMS Foldable ILEDs Glass R ~ 0.7mm R ~ 0.7mm ILED 200 μm 1 mm Professors: John A. Rogers, Placid Ferreira, Kent D. Choquette, Xiuling Li Postdoc: Y. Xiong Graduate Students: S.-I. Park, R.-H. Kim, P. Elvikis, M. Meitl, D.-H. Kim, J. Sulkin Fabrication of inorganic optoelectronic devices using nano- CEMMS manufacturing system.