Impact Excitation And Auger Quenching Processes In Er Doped Light Emitting Si Devices

1997 ◽  
Vol 486 ◽  
Author(s):  
G. Franzo' ◽  
F. Priolo ◽  
S. Coffa
Keyword(s):  
High Efficiency ◽  
Depletion Region ◽  
Light Signal ◽  
Impact Excitation ◽  
Light Emitting ◽  
Free Carriers ◽  
Heavily Doped ◽  
Excitation Processes ◽  
Er Doped ◽  
Incorporation Method

AbstractA detailed investigation of the Auger non radiative de-excitation processes, which compete with the radiative emission of Er in Si, will be presented. This process, in which the energy released by the Er de-excitation is transferred to free carriers, is demonstrated to be extremely efficient and characterized by an Auger coefficient CA˜4.4×l0−13 cm3/s. This Auger process and an efficient incorporation method have been used to improve the performances of Er implanted light emitting diodes. It will be shown that by exciting Er within the depletion region of reverse biased p+-n+ Si diodes in the breakdown regime, it is possible to avoid Auger quenching and to achieve high efficiency. Moreover, at the switch off of the diode, when the depletion region shrinks, the excited Er ions become suddenly embedded within the neutral heavily doped region. In this region Auger de-excitation with free carriers sets in allowing to modulate the light signal at frequencies as high as a few MHz.

Excitation Mechanisms and Light Emitting Device Performances in Er-Doped Crystalline Si

1996 ◽  
Vol 422 ◽  
Author(s):  
F. Priolo ◽  
S. Coffa ◽  
G. Franzo ◽  
A. Polman
Keyword(s):  
Reverse Bias ◽  
Crystalline Silicon ◽  
Forward Bias ◽  
Depletion Region ◽  
Impact Excitation ◽  
Electron Hole ◽  
Light Emitting ◽  
Temperature Operating ◽  
Excitation Mechanisms ◽  
Er Doped

AbstractIn this paper the performances of room temperature operating light emitting diodes (LEDs), fabricated by Er ion implantation of crystalline silicon, are investigated in detail. It is shown that 1.54 μm emission is observed under both forward and reverse bias operation, with a much higher intensity under reverse bias. The excitation mechanisms of Er3+ are demonstrated to be very different in the two cases: under forward bias Er is excited through the electron - hole recombination at an Er - related level, while under reverse bias impact excitation by hot carriers represents the excitation process. This last mechanism is shown to occur with a cross section of 6 × 10−17 cm2 and population inversion of the excitable Er sites within the depletion region is demonstrated. The efficiency and limitations of this approach are also discussed.

Excitation and De-Excitation Processes in Er Implanted Light Emitting Si Devices

1996 ◽  
Vol 438 ◽  
Author(s):  
G. Franzo' ◽  
S. Coffa ◽  
F. Priolo
Keyword(s):  
Room Temperature ◽  
Reverse Bias ◽  
High Efficiency ◽  
Internal Quantum Efficiency ◽  
Depletion Region ◽  
Light Emitting ◽  
Decay Lifetime ◽  
Long Lifetime ◽  
Region 10 ◽  
Excitation Processes

AbstractIn this paper we show that room temperature electroluminescence at 1.54 μm can be obtained in Er and O co-doped Si diodes, fabricated by ion implantation, under both forward and reverse bias conditions. This electroluminescence is particularly strong under reverse bias at the breakdown, when Er is excited through impact with hot carriers. This last mechanism is shown to occur with a cross section of 6×10-17 cm2. The measured decay lifetime of Er ions during pumping is 100 μs at room temperature and this allows to obtain a high internal quantum efficiency. However, when the diode is shut off, the decay lifetime becomes shorter and in particular it is less than 1.2 μs (that is the time response of our system). These results can be explained by the presence of Auger nonradiative de-excitation processes that are inhibited within the depletion region during pumping and set in when, at the shut off, the Er ions are immediately embedded within the heavily doped region (∼1019/cm3) of the device. The long lifetime (100 μs) during pumping and the very fast decay time (≤ 12 μs) at the diode shut off allow us to obtain, in our diode and under reverse bias, both a high efficiency (> 10-4) and a fast modulation (≥ 80 kHz) of the 1.54 μm emission.

Mbe Growth And Characterization Of Er/O And Er/F Doped Si Light Emitting Structures

1997 ◽  
Vol 486 ◽  
Author(s):  
W.-X. Ni ◽  
C.-X. Du ◽  
K. B Joelsson ◽  
G. V. Hansson ◽  
G. Pozina ◽  
...  
Keyword(s):  
Fold Increase ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Extended Defects ◽  
Hot Electron ◽  
Laser Applications ◽  
Light Emitting ◽  
Er Doping ◽  
Wide Range ◽  
Er Doped

AbstractBy using a low temperature growth process, Er doping in Si during MBE using Er2O3 or ErF3 as dopant sources has achieved a level of 5 × 1019 cm−3 without precipitation and generation of other extended defects. Luminescence properties of these Er-doped MBE Si structures have been extensively studied using both photon and hot electron impact excitation at a wide range of temperatures (2–300 K). It has been found that by incorporating C into Er/O doped layers, the room temperature EL emission with a FWHM value of 14 meV was ten times more intense than that with lower C doping. Post thermal annealing gave a strong effect on Er/F doped layers, leading to a 7-fold increase of the highest peak intensity while the peak line width reduced to 0.12 meV, which is very important for laser applications.

High efficiency and fast modulation of Er‐doped light emitting Si diodes

1996 ◽  
Vol 69 (14) ◽  
pp. 2077-2079 ◽  
Author(s):  
S. Coffa ◽  
G. Franzò ◽  
F. Priolo
Keyword(s):  
High Efficiency ◽  
Light Emitting ◽  
Er Doped

High-efficiency, long-lifetime deep-blue organic light-emitting diodes

2021 ◽  
Vol 15 (3) ◽  
pp. 208-215 ◽  
Author(s):  
Soon Ok Jeon ◽  
Kyung Hyung Lee ◽  
Jong Soo Kim ◽  
Soo-Ghang Ihn ◽  
Yeon Sook Chung ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Deep Blue ◽  
Organic Light ◽  
Long Lifetime

scholarly journals High efficiency blue organic light-emitting diodes with below-bandgap electroluminescence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Vasilopoulou ◽  
Abd. Rashid bin Mohd Yusoff ◽  
Matyas Daboczi ◽  
Julio Conforto ◽  
Anderson Emanuel Ximim Gavim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
High Mobility ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Material Interface ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Hole Transporting

AbstractBlue organic light-emitting diodes require high triplet interlayer materials, which induce large energetic barriers at the interfaces resulting in high device voltages and reduced efficiencies. Here, we alleviate this issue by designing a low triplet energy hole transporting interlayer with high mobility, combined with an interface exciplex that confines excitons at the emissive layer/electron transporting material interface. As a result, blue thermally activated delay fluorescent organic light-emitting diodes with a below-bandgap turn-on voltage of 2.5 V and an external quantum efficiency (EQE) of 41.2% were successfully fabricated. These devices also showed suppressed efficiency roll-off maintaining an EQE of 34.8% at 1000 cd m−2. Our approach paves the way for further progress through exploring alternative device engineering approaches instead of only focusing on the demanding synthesis of organic compounds with complex structures.

scholarly journals Effect of Optical and Morphological Control of Single-Structured LEC Device

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 843
Author(s):  
Woo Jin Jeong ◽  
Jong Ik Lee ◽  
Hee Jung Kwak ◽  
Jae Min Jeon ◽  
Dong Yeol Shin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Roughness ◽  
Surface Properties ◽  
High Efficiency ◽  
High Surface ◽  
Reduction Rate ◽  
Operating Characteristics ◽  
Emission Layer ◽  
Light Emitting ◽  
Stable Operating

We investigated the performance of single-structured light-emitting electrochemical cell (LEC) devices with Ru(bpy)3(PF6)2 polymer composite as an emission layer by controlling thickness and heat treatment. When the thickness was smaller than 120–150 nm, the device performance decreased because of the low optical properties and non-dense surface properties. On the other hand, when the thickness was over than 150 nm, the device had too high surface roughness, resulting in high-efficiency roll-off and poor device stability. With 150 nm thickness, the absorbance increased, and the surface roughness was low and dense, resulting in increased device characteristics and better stability. The heat treatment effect further improved the surface properties, thus improving the device characteristics. In particular, the external quantum efficiency (EQE) reduction rate was shallow at 100 °C, which indicates that the LEC device has stable operating characteristics. The LEC device exhibited a maximum luminance of 3532 cd/m2 and an EQE of 1.14% under 150 nm thickness and 100 °C heat treatment.

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