Ümit Özgür

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| ZnO is an attractive material for applications in electronics, photonics, acoustics, and sensing. In optical emitters, its high exciton binding energy (60 meV) gives ZnO an edge over other semiconductors such as GaN if reproducible and reliable p-type doping in ZnO were to be achieved, which currently remains to be the main obstacle for realization of(More)
Although started as red indicator lights based on the GaP:N system, replacing only the nixie (Numeric Indicator eXperimental No. 1) tube, LEDs have become quite a high performance device of late and are revolutionizing the display and illumination sectors of our economy. Presently, the GaN based light emitters adorn the automobiles, traffic lights, moving(More)
in InGaN light emitting diodes X. Ni, X. Li, J. Lee, S. Liu, V. Avrutin, Ü. Özgür, H. Morkoç, A. Matulionis, T. Paskova, G. Mulholland, and K. R. Evans Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, USA Semiconductor Physics Institute, A. Goštauto 11, 01108 Vilnius, Lithuania Kyma Technologies,(More)
Hybrid nanomaterials composed of metal-semiconductor components exhibit unique properties in comparison to their individual counterparts, making them of great interest for optoelectronic applications. Theoretical and experimental studies suggest that interfacial interactions of individual components are of paramount importance to produce hybrid electronic(More)
Optical transition energies and carrier dynamics in colloidally synthesized 2.0 ± 0.8 nm Ge1-xSnx quantum dots (x = 0.055-0.236) having visible luminescence were investigated using steady-state and time-resolved photoluminescence (PL) spectroscopy supported by first-principles calculations. By changing Sn content from x = 0.055 to 0.236, experimentally(More)
Aberration-corrected scanning transmission electron microscopy images of the In(0.15)Ga(0.85)N active region of a blue light-emitting diode, acquired at ~0.1% of the electron dose known to cause electron beam damage, show no lateral compositional fluctuations, but do exhibit one to four atomic plane steps in the active layer's upper boundary. The area(More)
Ge1-xSnx alloy quantum dots (QDs) were synthesized with sizes ranging from 1-3 nm exhibiting visible orange-red photoluminescence. Composition dependent optical properties were characterized and supported by theoretical calculations. Structural analysis suggests the QDs are diamond cubic phase, characteristic of Ge1-xSnx thin films and nanocrystals (NCs)(More)
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