Choi, Jun-Hyuk Korea Institute of Machinery & Materials

Transcription

1 The 11 th US-Korea Nanosymposium Choi, Jun-Hyuk Korea Institute of Machinery & Materials

2 About KIMM Nano-research Bldg Clean RM Five Research Divisions; 1. Advanced Manufacturing Sys. 2. Extreme Mechanical Eng. 3. Nano-Convergence Mechanical Systems 4. Environmental and Energy Sys. 5. Mechanical Systems Safety 2

3 Facilities/Infra. For Nanoimprint at wafer scale For Nanoimprint in Large area Master/Molds Large area Mold fabrication Etched master at 8 wafer 3/26

4 Metal patterning infrastructures Film Quality w.r.t. dep. rate Ag deposited By E-beam v.s. 5.0 A /S 0.5A /S Siliver Milling Test w.r.t. the variables of current, time, and tilting angle Target Sub. Tilting angle ~60 A Tilting angle ~0 Current 300 A Time 1min B 4/26

5 Outlines 1 Laboratory Introduction Members / Facility Researches for Nanoimprint 2 Fabrication strategies Introduction of various in-house self technologies Metal Imprint Transfer 3 Application to Optoelectronic Devices Photoluminescence Transparent electrode in Hybrid Cell Photovoltatics 4 Closing remarks

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7 Lift-off for well-round shaped Metal dots Process Scheme GT-IJPEN /26

8 Metal direct etch, Nanoimprint CMOS imaging chip + Plasmonic nano filter array + nanoimprint process Front Illumination &Reflection White Light Source SiO2 Al filter Si-wafer 8/26

9 Embedded Ag nanopatterning 1. Bilayer Hybrid NIL -> Lift-off 2. Metal Imprint Transfer Point of the embedded configuration on multilayer optoelectronics Non-uniform current flow (Leakage current) Reduced efficiency Electric field/electron injection enhancement Electron transport effects Thermal decay, reduced life-time Charge recommbination in solar cells Thermal decay, reduced efficiency 9/26

10 1. Bilayer Hybrid NIL and following Lift-off Process Scheme (a) (b) (b) Thermal Resist UV Resist Step (c) (c) (d) Step (d) (e) J. Nanophotonics 2014 Patent Step (e) (a) Half pre-cure of the coated UV resist (c) Thermal Imprint, UV exposure while pressed -> Complete cure of UV resist (d) Ag deposition by E-beam evaporation (e) Lift-off of thermal resist on top layer 10/26

11 200nm Ag array (embedded) 150nm Ag array (embedded) 265nm Ag array (embedded) 235nm Ag array (embedded) 11/26

12 2. Metal Imprint Transfer (a) Process Scheme Ag E-beam Evaporation (c) (d) Mold release UV Exposure (b) UV curable resist Spin-coated Half pre-cured Qz substrate (a) E-beam evaporation of Ag on mold pattern (b) Half pre-cure of UV curable resist (c) Only Ag on the top surface of mold in contact with half-cured resist, and UV exposure (d) Mold release Kor. Patent: , US Patent: 14/ Small 2014, Published Note: Embedded Dot Arrays 1) Half pre-cured UV-NIL resist 2) Limitedly Imprinted Depth via Pressure Control 3) Minimized Leakage Current at device depo. 12/26

13 Completely embedded Planar embedded Half embedded 13/26

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15 Metal Meshes in Hybrid Cell Process Scheme for Si-PEDOT Hybrid Photovoltaic cell 15/26

16 <Metal-based Meshes fabricated by Metal Imprint Transfer > T peak of 24 Ω/sq T peak of 16 Ω/sq T peak of 28 Ω/sq 16/26

17 17/26

18 Current density (ma/cm 2 ) Voc (V), Jsc (ma/cm 2 ) Au mesh (2 x 100 um) Au mesh (2 x 200 um) 5 Au mesh (2 x 300 um) 0 ITO Voltage (V) 2x100 2x200 2x300 ITO Au mesh size (um) Low shunt resistance PCE (%), FF (%) EQE (%) Au mesh (2x100 um) Au mesh (2x200 um) Au mesh (2x300 um) ITO Sample Wavelength (nm) V oc (mv) J sc (ma/cm 2 ) FF (%) PCE (%) ITO Au mesh (2x300 um) Au mesh (2x200 um) Au mesh (2x100 um) /26

19 Tunable Plasmonic Nanostructures Metal Imprint Transfer Annealing at > 150 C Confirmed Tunable plasmonic Properties Plasmonic peak shifts as annealing temperature increases. Green PL Intensity increased more than 400%, w.r.t. Ref. 19/26

20 Spectral Transmittance- Measured & Simulated 100 Anneal Temp. dependence at 200nm 80 Transmittance (%) B-40-1 B-40-2 B-40-3 B C 200 C 150 C R.T A-40-4 B-40-4 C-40-4 Wavelength (nm) Transmittance (%) nm 200nm Wavelength (nm) 265nm At 40nm, 250 (a) cylinder shape 에서 ellipsoidal 로변하는과정의 transmittance (b)~(d) Electric field intensity of cylinder shape & ellipsoidal shape with a,b=80nm 20/26

21 Photoluminescence Improvements <Annealing Temp.-dependence> incident light PL peak intensity Mold pattern size: 150nm Ag Thick: 40nm Anneal temp.: R.T./150/200/250 C Ref.glass Ref.NOA A-40-1 A-40-2 A-40-3 A-40-4 Double-grating excitation monochromator Incident light 5 5 glass Sample compartment 320 mm spectrograph with double-grating turret A/B/C ; 150/200/265-nm in mold pattern dia. 20/40/60; 20/40/60-nm in Ag thickness 1/2/3/4; RT/150/200/250 C for annealing temp Wavelength(nm) PL enhancement rate Sample w.r.t Ref. glass w.r.t. Ref-NOA A % 317% A % 303% A % 293% A % 518% 21/26

22 <Ag Thick.-dependence> <Mold pattern size.-dependence> PL peak intensity Mold pattern size: 150nm Anneal temp.: 250 C Ag Thick: 20/40/60-nm Ref.glass Ref.NOA A-20-4 A-40-4 A-60-4 PL peak intensity Mold pattern size: 150/200/265-nm Anneal temp.: 250 C Ag Thick: 40-nm Ref.glass Ref.NOA A-40-4 B-40-4 C Wavelength(nm) PL enhancement rate Sample w.r.t Ref. glass w.r.t. Ref-NOA A % 276% A % 518% A % 446% Wavelength(nm) PL enhancement rate Sample w.r.t Ref. glass w.r.t. Ref-NOA A % 518% B % 415% C % 200% 22/26

23 Closing Remarks Research Infrastructures for Nanostructures/Patterning Nanoimprint-based nanopatterning and its application in Optoelectronics Several approaches for metallic nanopattern fabrications in plasmonic fields Global Collaborations UC Berkeley-Micromechanical Analysis and Design (BMAD) IMRE, Singapore AMO GmbH Aachen Industrial Collaborations APN Hutem Co. nanolambda Korea Company Samsung Electronics-Manufacturing Institute Youngchang Chemical Co. Ltd 23/26

24 Members Nanoimprint - Process, Tools, Functional mater. - Appl.: R-RAM, Sensors, (O)LED 3D Multiscale Architecturing - Nanowire structuring - Nanomaterials self-assembly Plasmonic sensors, Light emitting - Metal nanostructuring - Metal NP. Self-growth Staffs Lee, Eung-sug: Ultrafind fabrication, Nanomechatronics Jeong, Jun-ho: Nanolithography, Nanoimprint Choi, Jun-hyuk: Metal nanopattering, Direct/Roll Imprint Choi, Dae-geun: Nanoimprint mater. Process chemistry Lee, Ji-hye: Nanowire, mask fabrication, biosensors Jeong, Joo-yeon: Electronics, Plasmonic optics 24/26

25 Thank you for your attentions

26 Research area <Nanopatterning, Lithography> <Metal nanopattern array> <Optoelectronic Applications> <Etching> <Optics-based Sensors> <Metal pattern, Lift-off> <Plasmonic Lithography> 26

27 Research directions Multilayer, Enlarged Solar cells Planarized Struc. Plasmonic Litho. Mask Plasmonic sensors Undercut 3D Struc. Optoelectronics Embedded structure profile Infrastructure of metallic nanopatterning