Zobrazeno 1 - 10
of 39
pro vyhledávání: '"Thomas M. Katona"'
Publikováno v:
Entrepreneurship Education and Pedagogy. 4:666-701
Over the past decade, universities have invested heavily in startup accelerator programs; however, their role in the university entrepreneurial ecosystem is ambiguous. Are university startup accelerators intended to educate or are they created to fac
Publikováno v:
Annual Review of Chemical and Biomolecular Engineering. 7:263-281
After decades of research and development on fabrication of efficient light-emitting diodes (LEDs) throughout the visible spectrum, LED-based lighting has reached unparalleled performance with respect to energy efficiency and has become the light sou
Autor:
C. J. Collins, Paul H. Shen, Michael Wraback, Xuhong Hu, J. Deng, Meredith Reed, Remis Gaska, Jianping Zhang, A. Lunev, Thomas M. Katona, Anand V. Sampath, Gregory A. Garrett, Yuriy Bilenko
Publikováno v:
International Journal of High Speed Electronics and Systems. 18:179-185
We present material and device characterization of 280 nm semiconductor ultraviolet light emitting diodes. These devices exhibit low series resistance, wavelength stability with increasing current, and have a half-life in excess of 570hrs, depending
Autor:
James S. Speck, Sven Einfeldt, Gene E. Ice, Thomas M. Katona, Wei Liu, Rozaliya Barabash, Robert F. Davis, C. Roder, Stephan Figge, Detlef Hommel, Steven P. DenBaars
Publikováno v:
physica status solidi (b). 243:1508-1513
The spatial distribution of strain, dislocations, and crystallographic orientation in uncoalesced and coalesced GaN layers grown on striped Si or SiC substrates was studied by polychromatic X-ray microdiffraction and high resolution monochromatic X-r
Autor:
Maxim S. Shatalov, R. Gaska, Michael Shur, Asif Khan, A. Lunev, J. Deng, Xiaobo Sharon Hu, Yuriy Bilenko, Thomas M. Katona, J. P. Zhang
Publikováno v:
physica status solidi (a). 203:1815-1818
We report on the development of AlGaN-based deep UV light emitting diodes (LEDs) with emission wavelengths from 254 to 340 nm, focusing on the improvement of 280 nm LEDs efficiency. Under optimal device structure the UV LEDs efficiency was found to s
Autor:
Thomas M. Katona, Stephan Figge, Oleg M. Barabash, C. Roder, James S. Speck, Rozaliya Barabash, Detlef Hommel, Gene E. Ice, Steven P. DenBaars, Robert F. Davis, Sven Einfeldt
Publikováno v:
physica status solidi (a). 203:142-148
Intrinsic stresses due to lattice mismatch, high densities of threading dislocations, and extrinsic stresses resulting from the mismatch in the coefficients of thermal expansion, are present in almost all III-Nitride heterostructures. Stress relaxati
Autor:
John F. Keading, Steven P. DenBaars, Shigefusa F. Chichibu, Takeyoshi Onuma, Akira Uedono, Thomas M. Katona, Umesh K. Mishra, P. Cantu, Shuji Nakamura, Stacia Keller, Takayuki Sota
Publikováno v:
Journal of Applied Physics. 95:2495-2504
Radiative and nonradiative processes in nearly strain-free AlxGa1−xN alloys were studied by means of steady-state and time-resolved (TR) photoluminescence (PL) spectroscopy, and the results were connected with that of positron annihilation measurem
Autor:
M. C. Schmidt, James S. Speck, Thomas M. Katona, Craig Moe, Hitoshi Tamura, Chihiro Funaoka, Steven P. DenBaars, Robert D. Underwood, Tal Margalith, Shuji Nakamura, H. Sato
Publikováno v:
physica status solidi (c). :2206-2209
UV LEDs with a peak emission wavelength of 336 nm were grown on a gallium nitride/sapphire substrate by inserting an AlN interlayer to prevent cracking. A maximum output power of 44 μW was achieved at 100 mA DC for 200 × 200 μm die wirebonded to a
Autor:
Christiane Poblenz, James S. Speck, D. S. Green, Chihiro Funaoka, Steven P. DenBaars, Hitoshi Sato, Thomas M. Katona, Hitoshi Tamura, P. Waltereit
Publikováno v:
physica status solidi (c). :2193-2197
Blue light emitting diodes (LEDs) were grown by rf-plasma assisted molecular beam epitaxy on GaN templates having threading dislocation densities of ∼8 × 107 and ∼1 × 109 cm−2. The dependence of light-current curves on device size indicated t
Publikováno v:
Journal of Physics D: Applied Physics. 36:A188-A191
Thin uncoalesced gallium nitride (GaN) layers grown on Si(111) by maskless cantilever epitaxy (CE) have been investigated using high resolution x-ray diffraction at variable temperatures. The crystallographic tilt of the free-hanging wings relative t