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EĞİTİM
ARAŞTIRMA
· MOCVD
(Metalorganic Chemical Vapor Deposition) ile ince filim ve
kristal büyütme
·
Mikrofabrikasyon ve Cihaz İşleme: Nitrür bazlı cihazların işlenmesi:
photolithography, reactive ion etching (RIE), inductively coupled plasma etching
(ICP), thin film deposition (PECVD, e-beam), RTA
·
Karakterizasyon:
Hall & TLM, PL, EL, I-V,
AFM,
X-RAY Diffraction, SEM Measurement Techniques and Analysis, Q - dielectric
factor measurements - Single Port Reflection Method with Network Analyzer
UCSB’de çalıştığı sürece Mitsubishi Chemical,
SSLDC (Solid State Lighting and Display Center) ve JST-ERATO (Japan Science and
Technology) projelerinde çalıştı ve finanse edildi.
· Amerikan Enerji Bakanlığı’nın 2020 yılına
kadar 98 milyar dolarlık enerji tasarrufu sağlanması projesi kapsamında
polarizasondan arınmış (non-polar) yarı-iletken III-Nitrürlerin malzeme
özellikleri, kristal kalitesi geliştirilmesi ve cihaz performanslarının
verimliliğinin arttırılması konusunda çalıştı. Bu uğurda;
· “Sidewall Lateral Epitaxial Overgrowth (SLEO)”
ismini verdiği, kristal içerisindeki deformasyon ve dislokasyonların
yoğunluklarını 103-104
kez indirgeyen yeni bir fabrikasyon ve büyütme tekniği geliştirdi. Bu yeni
teknik ile rapor edilmiş en düşük dislokasyon ve deformasyon yoğunluğunu düşük
maliyet ve zahmetle elde etti ve uluslararası bir patent aldı.
· m-yüzeyi denilen, (1-100)
oriyentasyonlu kristal yüzeyi üzerinde MOCVD (Metalorganic Chemical Vapor
Deposition) yöntemini kullanarak Dünya’da ilk kez cihaz yapma kalitesinde Nitrür
bazlı malzemeler büyüttü. Ve bu konuda uluslararası bir patent aldı.
· 360 nm UV dalga boyunda
çalışan, GaN/AlGaN kuantum kuyucuklu aktif bölgeden oluşmuş, yüksek elektron
hareketliliği ve rekor dahili kuantum verimliliği (internal quantum efficiency)
olan a-yüzeyi üzerine büyütülmüş LED’ler yaptı.
· AlGaN/GaN kuantum
kuyucuklarından oluşmuş LED yapılarının büyütülmesi, yapısal, elektriksel ve
optik karaketizasyonu konusunda Amerikan Ordu Laboratuvarları (Army Research
Labs) ile bir araştırma yürüttü.
PATENTLER
·
U.S. patent #
20060270076
”Defect Reduction of
Non-polar {11-20} a- and {1-100} m-plane GaN with Single-Step Sidewall Lateral
Epitaxial Overgrowth (SLEO)”, Bilge Imer, James S. Speck, Steven
P. DenBaars, submitted on March
30,2005 – granted on November 30, 2006.
·
U.S. patent #
20060270087
“Growth of non-polar
(1-100) m-plane GaN with Metalorganic Chemical Vapor Deposition (MOCVD)”,
Bilge Imer, James S. Speck, Steven P. DenBaars,
submitted on March 30,2005 – granted
on November 30, 2006.
YAYINLAR
A. HAKEMLİ YAYINLAR
I.
YAYINLANANLAR
(Agustos 2007 itibariyle toplam kaynak gösterilme 56)
1-”Structural and electrical
characterization of a-plane GaN grown on a-plane SiC”, M. D. Craven, A. Chakraborty, B. Imer, F. Wu, S. Keller, U. K.
Mishra, J. S. Speck, and S. P. DenBaars,
Phys. Stat.
Sol. (c) 0, No. 7, 2132-2135, October 2003
2- Microstructural evolution of
a-plane GaN grown on a-plane SiC by Metalorganic chemical vapor deposition”, M.
D. Craven, F. Wu, A. Chakraborty, B. Imer, U. K. Mishra, S. P.
DenBaars, and J. S. Speck, Applied Physics Letters,
Vol. 84, No.8, February 2004
3- ”Growth of thick (11-20) GaN
using a metal interlayer”, P. R. Tavernier, B. Imer, S. P.
DenBaars, and D. R. Clarke, Applied Physics Letters,
Vol. 85, No. 20, November 2004
4- “Intensity
Dependent Time-Resolved Photoluminescence Studies of GaN/AlGaN Multiple
Quantum Wells of Varying Well Width on Laterally Overgrown a‑plane and
Planar c-plane GaN “,(G. A. Garrett, H. Shen,
W. Wraback) from U.S. Army Research Laboratory, Sensors and Electron Devices
Directorate (B. Imer, B. Haskell, S. Keller, S. Nakamura, S. P.
DenBaars) from UCSB, Physica
Status Solidi (a), No. 5, 846 (2005)
5- “Polarized photoreflectance
spectroscopy of strained A-plane GaN films on R-plane sapphire”, (Sandip Ghosh,
Pranob Misra, and Holger T. Grahn) from Paul-Drude-Institut fur
Festk¨orperelektronik, Berlin, Germany (Bilge Imer, Shuji
Nakamura, S. P. DenBaars and J. S. Speck) from UCSB, J.
of Appl. Phys.,98, 026105, July 2005
6- “High Quality Non-polar ( a-plane
GaN with Sidewall Lateral Epitaxial Overgrowth (SLEO)”,
Bilge Imer, James S. Speck, Steven P. DenBaars,
Applied Physics Letters, Vol. 88, Number 6-061908,
February 2006
7- “Temperature-dependent radiative
lifetimes of excitons in non-polar GaN/AlGaN quantum wells”, (S. Rudin, G. A. Garrett, H. Shen, M. Wraback) from U.S. Army
Research Laboratort, Sensors and Electronic Devices Directorate ( B. Imer,
B. Haskell, J. S. Speck, S. Keller, S. Nakamura, and S. P. DenBaars) from UCSB,
IEEE International Semiconductor Device Research
Symposium, 2005 International Proceedings, Dec 7-9, 2005, pp. 225 -226
8-
“Polarization anisotropy in GaN films for different nonpolar orientations
studied by polarized photoreflectance spectroscopy”,(Pranob Misra, Udo Behn,
Oliver Brandt and Holger T. Grahn) from Paul-Drude-Institut fur
Festk¨orperelektronik, Berlin, Germany(Bilge Imer, Shuji Nakamura,
S. P. DenBaars and J. S. Speck) from UCSB, Applied
Physics Letters. Vol.88,Number 161920, April 2006
9-
“Optical polarization anisotropy in strained a-plane GaN films on r-plane
sapphire”, (Sandip Ghosh, Pranob Misra, and Holger T. Grahn) from Paul-Drude-Institut
fur Festk¨orperelektronik, Berlin, Germany (Bilge Imer, Shuji
Nakamura, S. P. DenBaars and J. S. Speck) from UCSB,
Physica Status Solidi (b). Vol.243,Number 7, pp. 1441 – 1445,
June 2006
10- “Stability of ( m-plane
GaN films grown by metalorganic chemical vapor deposition (MOCVD)”, Bilge
Imer, Feng Wu, Michael D. Craven, James S. Speck and Steven P. DenBaars,
Japanese Journal of Applied Physics, Vol. 45, No.
11, 8644, November 2006
11- “Growth evolution in Sidewall
Lateral Epitaxial Overgrowth (SLEO)”, Bilge Imer,
Feng Wu, James S. Speck, Steven P. DenBaars, Journal
of Crystal Growth, Vol. 306, 330-338, August 2007
II.
YAYIN AŞAMASINDA OLANLAR
12- “Improved efficiency nonpolar
a-plane GaN/AlGaN UV LEDs”, Bilge Imer,
Matt Schmidt, Ben Haskell, Barry Zhong, Kwang-choong Kim, Feng Wu, Tom Mates,
Stacia Keller, Shuji Nakamura, James S. Speck, and Steven P. DenBaars (In
review at Physica Status Solidi –a)
13- “Electrical Characterization of
low defect density nonpolar a-plane GaN grown with sidewall lateral epitaxial
overgrowth (SLEO)”, Bilge Imer,
Ben Haskell, Siddharth Rajan, Umesh K. Mishra, Shuji Nakamura, James S. Speck,
and Steven P. DenBaars (In review at Applied Physics Letters)
B. KONFERANSLAR
VE HAKEMSİZ YAYINLAR
1- “The 2000 Senior Technical
Symposium” April 11, 2000 University of Pittsburgh, Pittsburgh, PA
“Low Temperature Processing of High Q Dielectric Resonator
Ceramics for Microwave Dielectric Resonator Applications”, B. Imer,
I. Nettleship, P. P. Phule
2- 102nd
Annual Meeting & Exposition of American Ceramic Society, May 1, 2000, St.
Louis, MO
“Microstructure Evolution in BZT Ceramics Processed at Low
Temperature”, S.H. Ra, B. Imer, I. Nettleship, P.P. Phule
3- 2nd Annual
Review of Solid State Lightning an Display Center (SSLDC) in Fall 2003, Santa
Barbara
“Structural and Electrical Characterization of non-polar a-plane
GaN grown via MOCVD” B. Imer, M. D. Craven, S. Keller, U. K.
Mishra, S. P. DenBaars
4- IWNS
July 21, 2004, Pittsburgh, PA:
“Time-Resolved Photoluminescence Studies of LEO a-GaN and Planar
c-GaN MQW of Varying Well and Barrier Thickness”, (G. A. Garrett, A. V. Samapth,
J. Collins, M. Wraback) from U.S. Army Research Laboratory, Sensors and Electron
Devices Directory (B. Imer, B. Haskell, S. Keller, S. Nakamura, S.
P. DenBaars) from UCSB
5- “Nitride
Seminars” series for Interdisciplinary Center for Wide Bandgap Semiconductors
and The Solid State Lighting & Display Center, UCSB, Santa Barbara, CA, March 3,
2005
“A New Approach to Defect Reduction in Non-polar ( a-GaN”,
Bilge Imer, Feng Wu, James S. Speck, Steven P. DenBaars
6- 47th Electronic
Materials Conference (EMC), Santa Barbara, CA,
June 22-24, 2005
“Growth of Planar, Non-polar (1 -1 0 0) m-plane GaN over m-plane
SiC by Metalorganic Chemical Vapor Deposition (MOCVD)”, Bilge Imer,
Feng Wu, James S. Speck, Steven P. DenBaars
7- 6th
International Conference on Nitride Semiconductors (ICNS), Bremen, Germany,
August, 29- September, 2, 2005
“A New Approach to Defect Reduction in Non-polar ( a-GaN:
Sidewall Lateral Epitaxial Overgrowth (SLEO)”, Bilge Imer, Feng
Wu, James S. Speck, Steven P. DenBaars
8- 6th
International Conference on Nitride Semiconductors (ICNS), Bremen, Germany,
August, 29- September, 2, 2005
“Optical Polarization Anisotropy in Strained A-Plane GaN Films on
R-Plane Sapphire”, S. Gosh, P. Misra, H.T. Grahn, Bilge Imer, S.
Nakamura, S. P. DenBaars J. S. Speck
9- 4th Annual
Review of Solid State Lightning an Display Center(SSLDC) in Fall 2005, Santa
Barbara
“Sidewall Lateral Epitaxial Overgrowth (SLEO)”, B. Imer,
Feng Wu, James S. Speck, Steven P. DenBaars
10- IEEE
International Semiconductor Device Research Symposium, Dec. 7-9, 2005, Bethesda,
Maryland
“Temperature-depedent Radiative Lifetime of Excitons in Non-polar
GaN/AlGaN Quantum Wells”, (S. Rudin, G. A. Garrett, H. Shen, and M. Wraback)
from Army Research Labs (B. Imer, B. Haskell, J. S. Speck, S.
Keller, S. Nakamura, and S. P. DenBaars) from UCSB
11- The International
Symposium on Blue Laser and Light Emitting Diodes (ISBLLED) 2006, Montpellier,
France, May 2006
“Polarization Anisotropy in Nonpolar GaN films studied by
polarized photoreflectance spectroscopy”, Udo Behn,
Pranob Misra, Holger Grahn, Bilge Imer, Shuji Nakamura, Steven
DenBaars and James Speck
12- 28th
International Conference on the Physics of Semiconductors (ICPS), July
2006, Vienna, Austria,
“Temperature-dependent Radiative Lifetime of Excitons in
Non-polar GaN/AlGaN Quantum Wells”, S. Rudin, G. A. Garret, H. Shen, and M.
Wraback (from U.S. Army Research Laboratory, Sensors and Electron Devices
Directory) B. Imer, B. Haskell, J. S. Speck, S. Keller, S.
Nakamura, and Steven P. DenBaars (from UCSB)
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