Anomalous current-voltage characteristics of polymer light-emitting diodes

2002 ◽  
Vol 65 (11) ◽  
Author(s):  
Gui Yu ◽  
Yunqi Liu ◽  
Shuqin Zhou ◽  
Fenglian Bai ◽  
Pengju Zeng ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
Current Voltage ◽  
Polymer Light Emitting Diodes ◽  
Current Voltage Characteristics

Admittance Spectroscopy on Polymer Light-Emitting Diodes

2001 ◽  
Vol 665 ◽  
Author(s):  
P.W.M. Blom ◽  
H.C.F. Martens ◽  
H.B. Brom ◽  
J.N. Huiberts
Keyword(s):  
Light Emitting Diodes ◽  
Charge Carriers ◽  
Relaxation Processes ◽  
Admittance Spectroscopy ◽  
Charge Redistribution ◽  
Light Emitting ◽  
Current Voltage ◽  
High Bias ◽  
Polymer Light Emitting Diodes ◽  
Current Voltage Characteristics

ABSTRACTFrom admittance spectroscopy measurements on poly(p-phenylene vinylene) based light-emitting diodes various relaxation processes can be observed. At low bias inductive contributions due to the transit of charge carriers dominate, at high bias capacitive contributions as a result of charge redistribution appears. These processes reveal a transition from space-charge limited to recombination limited behavior, as is also indicated by the current-voltage characteristics.

Temperature and Field Dependence in Polymer Light Emitting Diodes

1999 ◽  
Vol 558 ◽  
Author(s):  
L. D. Bozano ◽  
S.A. Carter ◽  
J.C. Scott ◽  
G.G. Malliaras ◽  
P.J. Brock
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Phenylene Vinylene ◽  
Light Emitting ◽  
Current Voltage ◽  
Steady State Current ◽  
Polymer Light Emitting Diodes ◽  
Current Voltage Characteristics

ABSTRACTWe investigate the electrical properties of Polymer Light Emitting Diodes (LED's). The experimental data consists of steady state current-voltage characteristics and radiance as a function of temperature.The basic LED structure is Anode/MEH-PPV (2-methoxy,5-(2'-ethyl-hexyloxy)-l,4-phenylene vinylene)/Cathode, with a polymer film 120-140 nm thick. We use different anode/cathode pairs to study transport and light emission properties. Measurements of external quantum efficiency of bipolar and monopolar devices are presented from 200 K to 300 K. The electron and hole mobilities are derived in the trap-free limit and at high voltages.

Temperature and Field Dependence in Polymer Light Emitting Diodes

1999 ◽  
Vol 561 ◽  
Author(s):  
L. D. Bozano ◽  
S.A. Carter ◽  
J.C. Scott ◽  
G.G. Malliaras ◽  
P.J. Brock
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Phenylene Vinylene ◽  
Light Emitting ◽  
Current Voltage ◽  
Steady State Current ◽  
Polymer Light Emitting Diodes ◽  
Current Voltage Characteristics

ABSTRACTWe investigate the electrical properties of Polymer Light Emitting Diodes (LED's). The experimental data consists of steady state current-voltage characteristics and radiance as a function of temperature.The basic LED structure is Anode/MEH-PPV (2-methoxy,5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene)/Cathode, with a polymer film 120-140 nm thick. We use different anode/cathode pairs to study transport and light emission properties. Measurements of external quantum efficiency of bipolar and monopolar devices are presented from 200 K to 300 K. The electron and hole mobilities are derived in the trap-free limit and at high voltages.

Effect of deep-level states on current-voltage characteristics and electroluminescence of blue and UV light-emitting diodes

2010 ◽  
Vol 207 (6) ◽  
pp. 1489-1496 ◽  
Author(s):  
R. Nana ◽  
P. Gnanachchelvi ◽  
M. A. Awaah ◽  
M. H. Gowda ◽  
A. M. Kamto ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Deep Level ◽  
Uv Light ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

Cathode effect on current-voltage characteristics of blue light-emitting diodes based on a polyspirofluorene

2008 ◽  
Author(s):  
G. Garcia-Belmonte ◽  
E. M. Barea ◽  
Y. Ayyad-Limonge ◽  
J. M. Montero ◽  
H. J. Bolink ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

Electrical and Optical Characterisation of Homojjunction Gallium Nitride Light Emitting Diodes

1997 ◽  
Vol 482 ◽  
Author(s):  
G M Laws ◽  
J Morgan ◽  
G B Ren ◽  
I Harrison ◽  
E C Larkins ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Full Width Half Maximum ◽  
Light Emitting Diodes ◽  
Deep Level ◽  
Deep Level Emission ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

AbstractWe report on the fabrication and characterisation gallium nitride light emitting diodes (LEDs) grown by molecular beam epitaxy on (0001) oriented sapphire and (111)B GaAs substrates. The current voltage characteristics of the devices grown on sapphire show turn on voltages of between 4 and 5V with large on-series resistance of 600Ω; for corresponding devices grown on GaAs these parameters are between 6 and 7V and 150 Ω, respectively.Room temperature electroluminescence (EL) spectra from the GaN LEDs ,grown on sapphire substrates, show a dominant emission at 3.2 eV (397nm) with a full width half maximum (FWHM) of 335 meV which is attributed to free electron to acceptor transitions (e, A−Mg). A broad low intensity deep level emission is also observed centred at 2.4 eV (506nm). The peak of the EL from the devices grown on GaAs is at 3.1eV rather than 3.2eV. The differences between the two sets of devices are probably caused by the different device geometry.Preliminary results show that an “annealing” effect caused by electrical stressing resulted in an improvement of the EL spectra. The stressed samples show an increase in the near band edge emission intensity, a 20meV reduction in the FWHM and a significant reduction in the intensity of the deep level emission. The devices have a large 1/f noise contribution which does not appear to change after electrical stressing.

Neodymium-doped GaAs Light-emitting Diodes

1996 ◽  
Vol 422 ◽  
Author(s):  
S. J. Chang
Keyword(s):  
Quantum Efficiency ◽  
Breakdown Voltage ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Minority Carriers

Nd-doped semiconductor light-emitting diodes were fabricated by implanting Nd ions into a GaAs epi-layer. The fabricated GaAs:Nd diodes show good current-voltage characteristics with a typical reverse breakdown voltage between 8 and 12 V By injecting minority carriers into the diodes, Nd3+ related emissions were observed, at 77 K, in the 0.92, 1.11, and 1.3 μm regions. These electroluminescence signals correspond to the transitions from Nd3+4F3/2 state to the Nd3+4I9/2, 4I1/2, and 4I13/2 states, respectively. The measured external quantum efficiency of the GaAs:Nd diodes at 77 K, was 5 × 10−7.

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