Influence of Oxidized Layer on Operating Voltage and Luminance of Nanocrystalline Silicon Electroluminescent Device

2006 ◽  
Vol 6 (1) ◽  
pp. 200-204 ◽  
Author(s):  
Keisuke Sato ◽  
Kenji Hirakuri
Keyword(s):  
Luminescence Intensity ◽  
Luminescence Property ◽  
Radiative Recombination ◽  
Nanocrystalline Silicon ◽  
Operating Voltage ◽  
Si Substrate ◽  
Order Of Magnitude ◽  
Recombination Centers ◽  
Red Luminescence ◽  
Nanocrystalline Si

A direct current (DC) operating voltage and luminescence property of red electroluminescent (EL) devices with and/or without a silicon dioxide (SiO2) layer at interface between nanocrystalline Si(nc-Si) region and Si substrate has investigated. The removal of SiO2 layer in the EL device led to the lowering of DC operating voltage from 4.0 up to 2.0 V and the increase of luminescence intensity more than one order of magnitude. The external quantum efficiency of red luminescence from the EL device without the SiO2 layer at the DC operating voltage of 3.0 V was 0.5%. These were realized by the efficient and easy injection of carriers to the radiative recombination centers in the nc-Si region due to the removal of SiO2 layer. These results indicate that the removal of SiO2 layer is drastically improved the DC operating voltage and luminescence intensity for the nc-Si based EL device.

Improvement of Operating Voltage and Luminescent Properties in Nanocrystalline Silicon Electroluminescent Device

2004 ◽  
Vol 832 ◽  
Author(s):  
K. Sato ◽  
K. Hirakuri ◽  
T. Izumi
Keyword(s):  
Silicon Dioxide ◽  
Hydrofluoric Acid ◽  
Luminescent Properties ◽  
Nanocrystalline Silicon ◽  
Operating Voltage ◽  
Si Substrate ◽  
Naked Eye ◽  
Order Of Magnitude ◽  
Red Luminescence ◽  
Nanocrystalline Si

ABSTRACTWe have investigated direct current (DC) operating voltage and luminescence properties of electroluminescent (EL) devices with and/or without a silicon dioxide (SiO2) layer in nanocrystalline Si (nc-Si) region/Si substrate interface. The device with the SiO2 layer showed red luminescence with a peak at 670 nm by applying the DC operating voltage above 4.0 V. When the SiO2 layer in the device was completely removed by the hydrofluoric acid (HF) treatment, the red luminescence from the device was observed at the DC operating voltage of 2.0 V. Moreover, the luminescent intensity was also increased more than one order of magnitude, because carriers were efficiently and easily injected into the nc-Si region by the removal of SiO2 layer. The red luminescence from the device could be clearly seen with the naked eye under the DC operating voltage above 3.0 V. These results indicate that the removal of SiO2 layer leads to the lowering of DC operating voltage and increase of luminance for the nc-Si based EL device.

Enhancement of Green Electroluminescence from Nanocrystalline Silicon by Wet and Dry Processes

2006 ◽  
Vol 6 (1) ◽  
pp. 195-199 ◽  
Author(s):  
Keisuke Sato ◽  
Kenji Hirakuri
Keyword(s):  
Luminescence Property ◽  
Radiative Recombination ◽  
Annealing Temperature ◽  
Red Light ◽  
Solution Treatment ◽  
Surface Oxidation ◽  
Nanocrystalline Silicon ◽  
Green Luminescence ◽  
Spin Resonance ◽  
Recombination Centers

Correlation between defects and luminescence property from electroluminescent (EL) device composed of nanocrystalline silicon (nc-Si) prepared by wet and dry processes such as hydrofluoric (HF) acid solution treatment and annealing have investigated using electron spin resonance and EL measurements. The EL device using HF-treated nc-Si emitted strong red light, because of existence of only P′ce-centers (radiative recombination centers) on the surface vicinity. On the other hand, the EL device using annealed nc-Si above 400 °C exhibited green luminescence by the reduction of particle size due to surface oxidation. When the annealing temperature was risen from 400 °c up to 600 °c, the green luminescence strengthened with increasing the P′ce-centers. These results indicate that the formation of many radiative recombination centers onto the nc-Si surface vicinity lead to the enhancement of green luminescence from the nc-Si based EL device.

Enhancement of Electroluminescent Properties in Ethanol Dispersible Nanocrystalline Silicon Particles

2008 ◽  
Vol 8 (1) ◽  
pp. 374-378 ◽  
Author(s):  
Keisuke Sato ◽  
Naoki Kishimoto ◽  
Kenji Hirakuri
Keyword(s):  
Direct Current ◽  
Nanocrystalline Silicon ◽  
Nonradiative Recombination ◽  
Luminescent Intensity ◽  
Si Substrate ◽  
Current Voltage ◽  
Direct Current Voltage ◽  
Recombination Centers ◽  
Red Luminescence ◽  
Silicon Particles

We have fabricated two kinds of electroluminescent (EL) devices of which the luminous layer differs in order to improve an amount of injected carriers into the nanocrystalline silicon (nc-Si) particles. These EL devices showed red luminescence by the injection of carriers into the nc-Si particles after applying the direct current voltage. A large amount of carriers could be injected in the EL device prepared by the adhesion of ethanol dispersible nc-Si particles onto the dimples of Si substrate. The increase in the amount of injected carriers led to the enhancement of luminescent intensity. These results were achieved by the reduction of oxide layer surrounding nc-Si particles and the use of nc-Si particles without the nonradiative recombination centers (Pb centers).

Increased Conductivity in P-Type Hydrogenated Amorphous Silicon

1986 ◽  
Vol 70 ◽  
Author(s):  
Jacques I. Pankove ◽  
Joseph Dresner
Keyword(s):  
Atomic Hydrogen ◽  
Radiative Recombination ◽  
Dangling Bond ◽  
Dangling Bonds ◽  
Implantation Damage ◽  
Order Of Magnitude ◽  
Recombination Centers ◽  
Neutralization Process ◽  
P Type ◽  
Hydrogenated Amorphous

ABSTRACTThe low conductivity of B-doped a-Si:H is usually attributed to the fact that only a small fraction of the boron is tetrahedrally coordinated. In the presence of hydrogen, that small fraction can be inactivated via the acceptor-neutralization process that was described for the case of B-doped crystalline Si. When a B-doped sample of a-Si:H was annealed to drive away hydrogen near the boron atoms, the conductivity increases by a factor of 600. Although a-Si:H can be doped either n-type or p-type, the doping efficiency is orders of magnitude poorer than in crystalline Si. In fact the doping efficiency of boron is one order of magnitude lower than that of phosphorus. Several models account for the low doping efficiency of a-Si:H, the most plausible being the location of B in a trigonal site, i.e. surrounded by three Si-atoms as shown in Fig. 1. Such a center is neutral and cannot act as an acceptor. The present work is an offshoot of our study of the hydrogenation of dangling bonds in crystalline Si (1). The awareness that H ties to a Si dangling bond more strongly than another Si-atom led us to passivate the numerous dangling bonds on the surface a Si-crystal. Then, we passivated dangling bonds in grain boundaries and in dislocations and we showed that ion implantation damage also could be neutralized by atomic hydrogen thus removing non-radiative recombination centers and allowing the luminescent transitions to become more efficient.

Influence of Surface Electrode on Luminescent Properties of Nanocrystalline Silicon Electroluminescent Device

2007 ◽  
Vol 7 (2) ◽  
pp. 653-657 ◽  
Author(s):  
Keisuke Sato ◽  
Kenji Hirakuri
Keyword(s):  
Film Thickness ◽  
Indium Tin Oxide ◽  
Luminescent Properties ◽  
Nanocrystalline Silicon ◽  
Surface Electrode ◽  
High Brightness ◽  
Au Electrode ◽  
Ito Electrode ◽  
Order Of Magnitude ◽  
Red Luminescence

We describe the electrical and luminescence properties of nanocrystalline silicon (nc-Si) based red electroluminescent (EL) devices using an indium tin oxide (ITO) and/or gold (Au) films as a surface electrode, and the variation in the transmittance and resistivity of two electrodes with various film thicknesses. The increase in the film thickness from 50 to 200 nm of the ITO electrode led to the lowering of resistivity from 2.0 × 10−3 to 9.1 × 10−4 Ω cm and almost the same value (83–92%) of transmittance in the red region. On the other hand, the Au electrode was lowered the resistivity from 1.8 × 10−4 to 1.6 × 10−5 Ωcm and the transmittance in the red region from 42 to 1.8% with increasing the film thickness from 10 to 80 nm. Moreover, the red luminescence from the EL devices using the ITO and/or Au electrodes having thickness of 200 and 10 nm, respectively, obtained by applying the direct current forward voltage above 4.5 and 2.5 V and/or by flowing the forward current density above 53 and 38 mA/cm2, respectively. However, the luminescence intensity of EL device with the ITO electrode strengthened more than about one order of magnitude in comparison to that of the EL device with the Au electrode. This was due to the high value of transmittance in the red region of the ITO electrode. We suggest that the ITO electrode is an optimum surface electrode for the realization of nc-Si based EL device with the high brightness.

n-type GaN surface etched green light-emitting diode to reduce non-radiative recombination centers

2021 ◽  
Vol 118 (2) ◽  
pp. 021102
Author(s):  
Dong-Pyo Han ◽  
Ryoto Fujiki ◽  
Ryo Takahashi ◽  
Yusuke Ueshima ◽  
Shintaro Ueda ◽  
...  
Keyword(s):  
Radiative Recombination ◽  
Light Emitting Diode ◽  
Green Light ◽  
Light Emitting ◽  
Recombination Centers

&[mu]-Watt Enhanced Electroluminescent Power of Silicon Nanocrystal Light-Emitting Diodes Made on Nano-Scale Silicon-Tip-Array Substrate

2007 ◽  
Vol 989 ◽  
Author(s):  
Gong-Ru Lin ◽  
Chun-Jung Lin
Keyword(s):  
Light Emitting Diode ◽  
Optical Power ◽  
Oxide Semiconductor ◽  
Si Substrate ◽  
Light Emitting ◽  
Pillar Array ◽  
Turn On ◽  
Air Interface ◽  
Order Of Magnitude ◽  
Etching Mask

AbstractA Si nanocrystal based metal-oxide-semiconductor light-emitting diode (MOSLED) on Si nano-pillar array is preliminarily demonstrated. Rapid self-aggregation of Ni nanodots on Si substrate covered with a thin SiO2 buffered layer is employed as the etching mask for obtaining Si nano-pillar array. Dense Ni nanodots with size and density of 30 nm and 2.8×10 cm-2, respectively, can be formatted after rapid thermal annealing at 850°C for 22 s. The nano-roughened Si surface contributes to both the relaxation of total-internal reflection at device-air interface and the Fowler-Nordheim tunneling enhanced turn-on characteristics, providing the MOSLED a maximum optical power of 0.7 uW obtained at biased current of 375 uA. The optical intensity, turn-on current, power slope and external quantum efficiency of the MOSLED are 140 μW/cm2, 5 uA, 2+-0.8 mW/A and 1×10-3, respectively, which is almost one order of magnitude larger than that of a same device made on smooth Si substrate.

Photoluminescence of Pulsed Ruby Laser Annealed Crystalline and Ion Implanted GaAs

1981 ◽  
Vol 4 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Bernard J. Feldman
Keyword(s):  
Radiative Recombination ◽  
Laser Annealing ◽  
Laser Energy ◽  
Pulsed Laser ◽  
High Dose ◽  
Pulsed Laser Annealing ◽  
Recombination Centers ◽  
Pl Intensity ◽  
P Type ◽  
Ion Implanted

ABSTRACTIn an effort to understand the origin of defects earlier found to be present in p–n junctions formed by pulsed laser annealing (PLA) of ion implanted (II) semiconducting GaAs, photoluminescence (PL) studies have been carried out. PL spectra have been obtained at 4K, 77K and 300K, for both n–and p–type GaAs, for laser energy densities 0 ≤ El ≤ 0.6 J/cm2. It is found that PLA of crystalline (c−) GaAs alters the PL spectrum and decreases the PL intensity, corresponding to an increase in density of non-radiative recombination centers with increasing El. The variation of PL intensity with El is found to be different for n– and p–type material. No PL is observed from high dose (1 or 5×1015 ions/cm2 ) Sior Zn-implanted GaAs, either before or after laser annealing. The results suggest that the ion implantation step is primarily responsible for formation of defects associated with the loss of radiative recombination, with pulsed annealing contributing only secondarily.

Photoluminescence Study of Radiative Recombination in Porous Silicon

1993 ◽  
Vol 298 ◽  
Author(s):  
Chun Wang ◽  
Franco Gaspari ◽  
Stefan Zukotynski
Keyword(s):  
Porous Silicon ◽  
Excited States ◽  
Ground State ◽  
Radiative Recombination ◽  
Single Electron ◽  
Photoluminescence Study ◽  
Recombination Centre ◽  
Electron Center ◽  
Recombination Centers

AbstractPhotoluminescence has been studied in porous silicon. Two types of radiative recombination centers have been identified. One gives rise to luminescence at about 820 nm and is believed to be related to Si-H bonds. The second gives rise to luminescence at about 770 nm and is likely associated with S-O bonds. Above about 20K radiative recombination is assisted by excited states of the recombination centre located about 10 meV above the ground state. The Si-H recombination centre is a single electron center whereas the Si-O center appears to be a multi-electron center.

Carrier Transport and Lateral Conductivity in Nanocrystalline Silicon Layers

2000 ◽  
Vol 638 ◽  
Author(s):  
H. B. Kim ◽  
L. Montes ◽  
R. Krishnan ◽  
P. M. Fauchet ◽  
L. Tsybeskov
Keyword(s):  
Electrical Properties ◽  
Direct Current ◽  
Coulomb Blockade ◽  
Carrier Transport ◽  
Nanocrystalline Silicon ◽  
Conductivity Measurements ◽  
Si Nanocrystals ◽  
Ac Conductivity Measurements ◽  
Size Controlled ◽  
Nanocrystalline Si

AbstractWe have studied carrier transport and lateral electrical properties of nanocrystalline Si layers containing size controlled Si nanocrystals. Using results from direct current (dc) and alternating current (ac) conductivity measurements, the charging of Si nanocrystals and Coulomb blockade effect are discussed.

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