The Experts below are selected from a list of 73848 Experts worldwide ranked by ideXlab platform
Maria Antonietta Loi - One of the best experts on this subject based on the ideXlab platform.
-
exciton Diffusion Length in narrow bandgap polymers
Energy and Environmental Science, 2012Co-Authors: Oleksandr V Mikhnenko, Hamed Azimi, Markus Scharber, Mauro Morana, Paul W M Blom, Maria Antonietta LoiAbstract:We developed a new method to accurately extract the singlet exciton Diffusion Length in organic semiconductors by blending them with a low concentration of methanofullerene[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The dependence of photoluminescence (PL) decay time on the fullerene concentration provides information on both exciton Diffusion and the nanocomposition of the blend. Experimentally measured PL decays of blends based on two narrow band gap dithiophene–benzothiadiazole polymers, C–PCPDTBT and Si–PCPDTBT, were modeled using a Monte Carlo simulation of 3D exciton Diffusion in the blend. The simulation software is available for download. The extracted exciton Diffusion Length is 10.5 ± 1 nm in both narrow band gap polymers, being considerably longer than the 5.4 ± 0.7 nm that was measured with the same technique in the model compound poly(3-hexylthiophene) as a reference. Our approach is simple, fast and allows us to systematically measure and compare exciton Diffusion Length in a large number of compounds.
-
Exciton Diffusion Length in narrow bandgap polymers
Energy & Environmental Science, 2012Co-Authors: Oleksandr V Mikhnenko, Hamed Azimi, Markus Scharber, Mauro Morana, Paul W M Blom, Maria Antonietta LoiAbstract:We developed a new method to accurately extract the singlet exciton Diffusion Length in organic semiconductors by blending them with a low concentration of methanofullerene[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The dependence of photoluminescence (PL) decay time on the fullerene concentration provides information on both exciton Diffusion and the nanocomposition of the blend. Experimentally measured PL decays of blends based on two narrow band gap dithiophene-benzothiadiazole polymers, C-PCPDTBT and Si-PCPDTBT, were modeled using a Monte Carlo simulation of 3D exciton Diffusion in the blend. The simulation software is available for download. The extracted exciton Diffusion Length is 10.5 ± 1 nm in both narrow band gap polymers, being considerably longer than the 5.4 ± 0.7 nm that was measured with the same technique in the model compound poly(3-hexylthiophene) as a reference. Our approach is simple, fast and allows us to systematically measure and compare exciton Diffusion Length in a large number of compounds. cop. 2012 The Royal Society of Chemistry.
Y Rosenwaks - One of the best experts on this subject based on the ideXlab platform.
-
measuring minority carrier Diffusion Length using a kelvin probe force microscope
Physical Review B, 2000Co-Authors: Rafi Shikler, T Meoded, N Fried, Y RosenwaksAbstract:A method based on Kelvin probe force microscopy for measuring minority-carrier Diffusion Length in semiconductors is described. The method is based on measuring the surface photovoltage between the tip of an atomic force microscope and the surface of an illuminated semiconductor junction. The photogenerated carriers diffuse to the junction and change the contact potential difference between the tip and the sample, as a function of the distance from the junction. The Diffusion Length L is then obtained by fitting the measured contact potential difference using the minority-carrier continuity equation. The method was applied to measurements of electron Diffusion Length in GaP $\mathrm{pn}$ and Schottky junctions. The measured Diffusion Length was found to be $\ensuremath{\sim}2 \ensuremath{\mu}\mathrm{m},$ in good agreement with electron beam induced current measurements.
-
direct measurement of minority carriers Diffusion Length using kelvin probe force microscopy
Applied Physics Letters, 1999Co-Authors: T Meoded, Rafi Shikler, N Fried, Y RosenwaksAbstract:We report on the use of Kelvin force microscopy as a method for measuring very short minority carrier Diffusion Length in semiconductors. The method is based on measuring the surface photovoltage between the tip of an atomic force microscope and the surface of an illuminated semiconductor junction. The photogenerated carriers diffuse to the junction, and change the contact potential difference between the tip and the sample as a function of the distance from the junction edge. The Diffusion Length L is then obtained by fitting the measured contact potential difference using the minority carrier continuity equation. The method is applied to measurements of electron Diffusion Lengths in GaP epilayers.
Eugene B. Yakimov - One of the best experts on this subject based on the ideXlab platform.
-
Diffusion Length AND EFFECTIVE CARRIER LIFETIME IN III-NITRIDES
International Journal of Nanoscience, 2007Co-Authors: N. M. Shmidt, A. N. Titkov, Eugene B. YakimovAbstract:The results of excess carrier Diffusion Length investigations in GaN and in the light emitting structures (LES) based on MQW InGaN/GaN with different ordering of mosaic structures are presented. It is confirmed that the Diffusion Length values in these structures indeed are essentially lower than 1 μm. The Electron Beam Induced Current investigations have shown that the effective Diffusion Length measured on GaN structures could be determined by the mosaic domain boundary effect on the excess carrier transport. Such nanosize domains could also determine the lateral localization in the MQW light emitting diodes. The mosaic structure ordering effect on the quantum efficiency of LES and high values of the effective carrier lifetime in well-ordered LES are discussed.
-
mapping of Diffusion Length and depletion region width in schottky diodes
Semiconductor Science and Technology, 1992Co-Authors: O V Kononchuk, Eugene B. YakimovAbstract:The possibilities of depletion region width (W) and minority carrier Diffusion Length mapping using the electron-beam-induced capacitance (EBIcap) mode and measurements of d/c/dW are discussed. A model of EBIcap signal formation is proposed. It is shown that these techniques are more suitable than electron-beam-induced current (EBIC) for local measurements and mapping of W.
-
mapping of Diffusion Length and depletion region width in schottky diodes
Semiconductor Science and Technology, 1992Co-Authors: O V Kononchuk, Eugene B. YakimovAbstract:The possibilities of depletion region width (W) and minority carrier Diffusion Length mapping using the electron-beam-induced capacitance (EBIcap) mode and measurements of d/c/dW are discussed. A model of EBIcap signal formation is proposed. It is shown that these techniques are more suitable than electron-beam-induced current (EBIC) for local measurements and mapping of W.
Oleksandr V Mikhnenko - One of the best experts on this subject based on the ideXlab platform.
-
systematic study of exciton Diffusion Length in organic semiconductors by six experimental methods
Materials horizons, 2014Co-Authors: Jason D A Lin, Oleksandr V Mikhnenko, Jingrun Chen, Zarifi Masri, Arvydas Ruseckas, Alexander Mikhailovsky, Reilly P Raab, Jianhua Liu, Paul W M BlomAbstract:Six experimental methods have been used to investigate the exciton Diffusion Length in materials with systematic chemical modifications. We find that exciton Diffusion Length correlates with molecular ordering. We discuss situations in which certain experimental techniques are more appropriate.
-
exciton Diffusion Length in narrow bandgap polymers
Energy and Environmental Science, 2012Co-Authors: Oleksandr V Mikhnenko, Hamed Azimi, Markus Scharber, Mauro Morana, Paul W M Blom, Maria Antonietta LoiAbstract:We developed a new method to accurately extract the singlet exciton Diffusion Length in organic semiconductors by blending them with a low concentration of methanofullerene[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The dependence of photoluminescence (PL) decay time on the fullerene concentration provides information on both exciton Diffusion and the nanocomposition of the blend. Experimentally measured PL decays of blends based on two narrow band gap dithiophene–benzothiadiazole polymers, C–PCPDTBT and Si–PCPDTBT, were modeled using a Monte Carlo simulation of 3D exciton Diffusion in the blend. The simulation software is available for download. The extracted exciton Diffusion Length is 10.5 ± 1 nm in both narrow band gap polymers, being considerably longer than the 5.4 ± 0.7 nm that was measured with the same technique in the model compound poly(3-hexylthiophene) as a reference. Our approach is simple, fast and allows us to systematically measure and compare exciton Diffusion Length in a large number of compounds.
-
Exciton Diffusion Length in narrow bandgap polymers
Energy & Environmental Science, 2012Co-Authors: Oleksandr V Mikhnenko, Hamed Azimi, Markus Scharber, Mauro Morana, Paul W M Blom, Maria Antonietta LoiAbstract:We developed a new method to accurately extract the singlet exciton Diffusion Length in organic semiconductors by blending them with a low concentration of methanofullerene[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The dependence of photoluminescence (PL) decay time on the fullerene concentration provides information on both exciton Diffusion and the nanocomposition of the blend. Experimentally measured PL decays of blends based on two narrow band gap dithiophene-benzothiadiazole polymers, C-PCPDTBT and Si-PCPDTBT, were modeled using a Monte Carlo simulation of 3D exciton Diffusion in the blend. The simulation software is available for download. The extracted exciton Diffusion Length is 10.5 ± 1 nm in both narrow band gap polymers, being considerably longer than the 5.4 ± 0.7 nm that was measured with the same technique in the model compound poly(3-hexylthiophene) as a reference. Our approach is simple, fast and allows us to systematically measure and compare exciton Diffusion Length in a large number of compounds. cop. 2012 The Royal Society of Chemistry.
T. C. Mcgill - One of the best experts on this subject based on the ideXlab platform.
-
electron Diffusion Length and lifetime in p type gan
Applied Physics Letters, 1998Co-Authors: Zvonimir Z Bandic, P M Bridger, Eric C. Piquette, T. C. McgillAbstract:We report on electron beam induced current and current–voltage (I–V) measurements on Schottky diodes on p-type doped GaN layers grown by metal organic chemical vapor deposition. A Schottky barrier height of 0.9 eV was measured for the Ti/Au Schottky contact from the I–V data. A minority carrier Diffusion Length for electrons of (0.2 ± 0.05) µm was measured for the first time in GaN. This Diffusion Length corresponds to an electron lifetime of approximately 0.1 ns. We attempted to correlate the measured electron Diffusion Length and lifetime with several possible recombination mechanisms in GaN and establish connection with electronic and structural properties of GaN.
-
minority carrier Diffusion Length and lifetime in gan
Applied Physics Letters, 1998Co-Authors: Zvonimir Z Bandic, P M Bridger, Eric C. Piquette, T. C. McgillAbstract:Electron beam induced current measurements on planar Schottky diodes on undoped GaN grown by metalorganic chemical vapor deposition are reported. The minority carrier Diffusion Length of 0.28 μm has been measured, indicating minority carrier lifetime of 6.5 ns. The tapping mode atomic force microscopy imaging of the surfaces and scanning electron microscopy of the cross sections have been used to characterize the linear dislocations and columnar structure of the GaN. The possible influence of recombination on the extended defects in GaN on the minority carrier Diffusion Length and lifetime is discussed, and contrasted to other recombination mechanisms.