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About Omics Group

About Omics Group.

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About Omics Group

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  1. About Omics Group OMICS Group International through its Open Access Initiative is committed to make genuine and reliable contributions to the scientific community. OMICS Group hosts over 400 leading-edge peer reviewed Open Access Journals and organize over 300 International Conferences annually all over the world. OMICS Publishing Group journals have over 3 million readers and the fame and success of the same can be attributed to the strong editorial board which contains over 30000 eminent personalities that ensure a rapid, quality and quick review process. 

  2. About Omics Group conferences • OMICS Group signed an agreement with more than 1000 International Societies to make healthcare information Open Access. OMICS Group Conferences make the perfect platform for global networking as it brings together renowned speakers and scientists across the globe to a most exciting and memorable scientific event filled with much enlightening interactive sessions, world class exhibitions and poster presentations • Omics group has organised 500 conferences, workshops and national symposium across the major cities including SanFrancisco,Omaha,Orlado,Rayleigh,SantaClara,Chicago,Philadelphia,Unitedkingdom,Baltimore,SanAntanio,Dubai,Hyderabad,Bangaluru and Mumbai.

  3. GaN Compound Semiconductors for Ultraviolet, Visible, and Terahertz Photonics Prof. Can Bayram, Innovative COmpoundsemiconductoR Laboratory (ICORLAB) Assistant Professor, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, IL, USA EMAIL: cbayram@Illinois.edu WEBPAGE: icorlab.ece.Illinois.edu September 9, 2014 2nd International Conference and Exhibition on Lasers, Optics, and Photonics , Philadelphia, USA COLLABORATORS: M. Razeghi, *Center for Quantum Devices, Department of Electrical Engineering and Computer Science, Northwestern University, IL USA S. Bedell, J. Kim, H. Park, C. Cheng, J. Ott, K. Reuter, and D. Sadana, *IBM Thomas J. Watson Research Center, NY, USA C. Dimitrakopoulos, *Department of Chemical Engineering, University of Massachusetts, MA, USA

  4. OUTLINE • Gallium Nitride Photonics • Ultraviolet Technology • Next Phase (i.e. hexagonal vs. cubic) • Visible Light Emitting Diodes • Vertical Thinking (i.e. lateral vs. vertical) • Terahertz Technology • Room-Temperature Operation • Conclusion

  5. Gallium Nitride PhotonicsApplications Cancer Detection Water Disinfection Lighting Concealed Weapons Detection Bio-Agent Detection Data Storage 200 nm 700 nm Wavelength 360 nm 300 µm mW W Power ULTRAVIOLET VISIBLE TERAHERTZ

  6. III-V MaterialsConventional III-V Materials : As/P-based INDIRECT Energy conduction band Bandgap ~2.4 eV Wavevector AlP valence band 0.5 mm DIRECT Energy InSb conduction band 3.5 mm Bandgap ~0.35 eV Wavevector valence band PhD Thesis by Can Bayram (2011) http://www.ioffe.ru/SVA/NSM/

  7. III-V MaterialsEmerging III-V Materials : N-based Al N 200 nm N Al Ultraviolet Ga In 400 nm Ga N Ga N Visible 800 nm Infrared 1700 nm In N PhD Thesis by Can Bayram (2011); http://www.ioffe.ru/SVA/NSM/

  8. OUTLINE • Gallium Nitride Photonics • Ultraviolet Technology • Next Phase (i.e. hexagonal vs. cubic) • Visible Light Emitting Diodes • Vertical Thinking (i.e. lateral vs. vertical) • Terahertz Technology • Room-Temperature Operation • Conclusion Disinfection

  9. Ultraviolet Technology Engineering UV LEDs for E-coli Targetting (λ~280 nm) Device Structure Targetting Emission Wavelength Multi-Quantum-Well P-Contact Layer 50 nm p-GaN Vegard’s Law (+) BARRIER: Al0.40Ga0.60N 10 nm BULK 50 nm p-Al0.45Ga0.55N 20 nm p-Al0.7Ga0.3N Multi-Quantum-Well (+) 100 nm n-Al0.45Ga0.55N QUANTUM (+) 1 mm n+-Al0.55Ga0.45N N-Contact Layer Design Parameters CB CB (-) VB STARK VB VB λ≈280 nm Al0.85Ga0.15N/AlN SL Electroluminescence I-V Curve Buffer 350 nm AlN CB WELL:5 nm Al0.36Ga0.64N (0001) Sapphire BARRIER: Al0.40Ga0.60N 10 nm Substrate 0.11 4.41 eV 0.15 eV 4.45 eV = + - (278 nm)

  10. Ultraviolet Technology Germicidal Flashlights (λ~265, 280, 340 nm) Spectrum Near-Field Image Packaged UV LED Die 300 µm 50 mm 15 cm UV Flashlights Battery PhD Theses. AlirezaYasan (2006); Ryan McClintock (2007), Can Bayram (2011)

  11. Ultraviolet Technology Going Beyond Conventional LEDs: Understanding Polarization Wurtzite Lattice Unit Wurtzite Lattice Unit Under stress At equilibrium Tetrahedral Arrangement PSP Ga Ga c c' PSP PPZ Stress Stress PSP N PSP PSP N a a' N Ga + Total Polarization (P) = P spontaneous (PSP) P piezoelectric (PPZ) composition stress Al, Ga, In content Lattice & Thermal mismatch & Total Polarization (P) Polarization effects in semiconductors, Springer (2008)

  12. Ultraviolet Technology Going Beyond Conventional LEDs: Droop-free Approach Visible LEDs & Droop DROOP RED LED UV LED BLUE LED GREEN LED   Appl. Phys. Express 4, 012101, (2011); PhD Thesis by Won Seok Lee (2011); PhD Thesis by Can Bayram (2011); Appl. Phys. Lett. 102, 011106 (2013) 

  13. Ultraviolet Technology Going Beyond Conventional LEDs: Polarization-free Emitters Novel U-Patterning Ge GaAs SiO2 SiO2 SiO2 SiO2 Si(100) Si(100) GaN SiO2 SiO2 Si(100) Adv. Funct. Mater.. 24 (28) 4491(2014)

  14. Ultraviolet Technology Going Beyond Conventional LEDs: Polarization-free Emitters MOCVD Process Novel U-Patterning Selective Silicon diffraction GaN Zincblende diffraction GaN XRD Phase Boundaries • Selective • Single Crystal • Single phase • Controlled SiO2 SiO2 Si(100) Adv. Funct. Mater.. doi: 10.1002/adfm.201304062 (2014) Adv. Funct. Mater.. 24 (28) 4491(2014)

  15. Ultraviolet Technology Going Beyond Conventional LEDs: Polarization-free Emitters Eliminating Polarization Going Polarization-Free Preliminary Demonstration New zincblende Conventional wurtzite MQW zincblende GaN P wurtzite Preliminary Demonstration Adv. Funct. Mater.. doi: 10.1002/adfm.201304062 (2014) Adv. Funct. Mater.. 24 (28) 4491(2014)

  16. OUTLINE • Gallium Nitride Photonics • Ultraviolet Technology • Next Phase (i.e. hexagonal vs. cubic) • Visible Light Emitting Diodes • Vertical Thinking (i.e. lateral vs. vertical) • Terahertz Technology • Room-Temperature Operation • Conclusion Lighting

  17. Light Emitting Diodes Vertical Thinking Lateral Architecture Optical Laser Liftoff Mechanical Stress Vertical Architecture contact Cross-section Cross-section Cross-section Cross-section light light current crowding LED stack contact contact contact UV Laser substrate (2-inch) mm2 (~1mm2) Bending Stiffness (Thickness)3 http://www.photonics.com/ Adv. Funct. Mater. 18, 2673–2684 (2008); Advanced Energy Materials 3 (5), 566–571(2013) Applied Physics Express 6 (11), 112301 (2013)

  18. Light Emitting Diodes Mechanical Stress & Release: Novel Means for Thin-film Devices A Failure Mechanism Photograph of 4-inch Flexible Ge/InGaAs/InGaP Solar Cell J-V characteristics Stress-guided Chipping BULK THIN FILM SOLAR CELLS Highest Specific Power ~ 2000 W/kg Photograph of 2-inch (In)GaN-based Thin Film LED Electroluminescence BULK THIN FILM Mechanical Release LEDs stressor Largest Area Thin-film LEDs ~ 75 cm2 opening shear Advanced Energy Materials 3 (5), 566–571 (2013);Applied Physics Express 6 (11), 112301 (2013)

  19. Light Emitting Diodes A Revolutionary Strategy for GaN Devices IN PRESS C. Bayram, J. Kim et. al. Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene Nature Communications. IN PRESS (2014)

  20. Light Emitting Diodes A Revolutionary Strategy: GaN on Graphene for Thin Film Devices Graphitization of SiC Ni stressor deposition Epitaxy of GaN on graphene Ni GaN GaN Graphene Graphene SiC SiC SiC Graphene/SiC Return for reuse Removal of tape and Ni Transfer on arbitrary substrate Layer release Tape Tape Ni Ni GaN Graphene GaN GaN Silicon Silicon SiC Nature Communications. IN PRESS (2014)

  21. Light Emitting Diodes Release & Reuse Through Graphene Cleave Layer Raman Spectra GaN Epitaxy Ni stressor Transfer Mechanical Release released GaN on Ni REUSE tape host substrate GaN on Insulator Fresh Reused RMS roughness ~3 Å 1 µm 3 µm Nature Communications. IN PRESS (2014)

  22. Light Emitting Diodes A Novel Application: Thin-film Blue LEDs Structure Active Area Photoluminescence X-ray Diffraction experiment simulation light 100 nm 1 µm 1 cm I-V Curve Electroluminescence n-contact at 10 mA p-contact Nature Communications. IN PRESS (2014)

  23. OUTLINE • Gallium Nitride Photonics • Ultraviolet Technology • Next Phase (i.e. hexagonal vs. cubic) • Visible Light Emitting Diodes • Vertical Thinking (i.e. lateral vs. vertical) • Terahertz Technology • Room-Temperature Operation • Conclusion Concealed Weapons Detection

  24. GaN-based Intersubband Devices Motivation • Intersubband transitions are three orders of magnitude faster • than interband ones. • Material systems in near-infarred • AlAs/InGaAs • AlAsSb/InGaAs • BeTe/ZnSe • AlN/GaN SLs posses • large conduction bandoffset (~2.1 eV) • large LO phonon energy (~90 meV) • large electron effective mass (0.2×m0) CB Intersubband transition • Very well thin widths • Picosecond transitions Interband transition • Tunibility in a wide range • RT operation • Femtosecondtransitions VB Comparison: GaAs vs. GaN for 1.55 µm devices • Transition speed in • AlGaN is ~ 100 femtosecond vs. InGaAs is ~1-10 picosecond. • Required width of • (Al)GaN well is ~ 8 ML vs InGaAs well is ~ 2 ML

  25. Infrared Technology World’s First GaN-based Infrared Devices Tunability in the Infrared via Al-content Active Layer Structure Low Al Content High Al Content • First GaN-based infrared devices: • Shortest wavelength: 1.0 µm (by MOCVD) • Longest wavelength: 5.3 µm Bayram C. J. Appl. Phys. 111, 013514 (2012); Bayram et al. Appl. Phys. Lett. 95, 131109 (2009); Bayram et al. Appl. Phys. Lett. 95, 201906 (2009).

  26. Resonant Tunneling Diodes World’s First GaN-based Reliable and Reproducible RTDs Negative Resistance in RT and 77 K Device Structure • First GaN-based resonant tunneling diodes: • Reproducible I-V curves; • Tunneling at room and low temperatures. Quantum Devices THz Oscillators Bayram et al. Appl. Phys. Lett. 97, 181109 (2010)

  27. Summary • GaN can have global impact through • Ultraviolet light source with germicidal effects. • Visible light sources for general illumination. • Terahertz emitters operating at room temperature. SiO2 SiO2 Si(100) • Vertical thinking is critical for enabling innovative and exciting opportunities for GaNdevices • Polarization-free design • Vertical architecture PhD Thesis. Can Bayram (2011) Adv. Funct. Mater.. doi: 10.1002/adfm.201304062 (2014) Nature Nanotechnology. Under External Referee Review (2014)

  28. Let Us Meet Again We welcome all to our future group conferences of Omics group international Please visit: www.omicsgroup.com www.Conferenceseries.com http://optics.conferenceseries.com/

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