Blue Light Electroluminescence From Doped μc-SiC prepared by Excimer (ArF) Laser Crystallisation

1994 ◽  
Vol 339 ◽  
Author(s):  
S. P. Lau ◽  
J. M. Marshall ◽  
T. E. Dyer ◽  
A. R. Hepburn ◽  
J. F. DaVies
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Chemical Vapour ◽  
Wide Band ◽  
Dark Conductivity ◽  
Carrier Injection ◽  
Large Area ◽  
Fully Integrated ◽  
Novel Method ◽  
Arf Laser

ABSTRACTA novel method has been developed to prepare highly conductive and wide band gap doped (B2H6/PH3) microcrystalline silicon carbide (μ-SiC) by excimer (ArF) laser crystallisation. Doped a-SiC:H films were prepared by Plasma Enhanced Chemical Vapour Deposition (PECVD), both with and without H2 dilution. After crystallisation, this material has Taue gap of around 2.0 eV and exhibits a dark conductivity as high as 20 (Ωcm)-1, more than ten orders of magnitude higher than before the laser irradiation. This is shown to be mainly due to the formation of SiC microcrystallites in the laser crystallised a-SiC:H.In this paper, we report that this material can be utilised not only as the carrier injection layer in a-SiC:H based Thin Film Light Emitting Diodes (TFLEDs) but also as a luminescent layer. Blue light emission has been observed from a laser crystallised (LC) doped μc-SiC based electroluminescent device, the peak wavelength is around 490nm.The simplicity of excimer (ArF) laser crystallisation and its capability to fabricate poly-Si TFTs, makes this a promising novel method to realise fully integrated Si large area multi-colour displays.

LUMINESCENCE BEHAVIOR AND MECHANISM OF LIGHT-EMITTING POROUS SILICON

1994 ◽  
Vol 08 (02) ◽  
pp. 69-92 ◽  
Author(s):  
XUN WANG
Keyword(s):  
Porous Silicon ◽  
Blue Light ◽  
Light Emission ◽  
Energy State ◽  
Surface Recombination Velocity ◽  
Luminescence Spectroscopy ◽  
Carrier Injection ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Si Nanostructures

In this review article, we give a new insight into the luminescence mechanism of porous silicon. First, we observed a “pinning” characteristic of photoluminescent peaks for as-etched porous silicon samples. It was explained as resulting from the discontinuous variation of the size of Si nanostructures, i.e. the size quantization. A tight-binding calculation of the energy band gap widening versus the dimension of nanoscale Si based on the closed-shell Si cluster model agrees well with the experimental observations. Second, the blue-light emission from porous silicon was achieved by using boiling water treatment. By investigating the luminescence micrographic images and the decaying behaviors of PL spectra, it has been shown that the blue-light emission is believed to be originated from the porous silicon skeleton rather than the surface contaminations. The conditions for achieving blue light need proper size of Si nanostructures, low-surface recombination velocity, and mechanically strong skeleton. The fulfillment of these conditions simultaneously is possible but rather critical. Third, the exciton dynamics in light-emitting porous silicon is studied by using the temperature-dependent and picosecond time-resolved luminescence spectroscopy. A direct evidence of the existence of confined excitons induced by the quantum size effect has been revealed. Two excitation states are found to be responsible for the visible light emission, i.e. a higher lying energy state corresponding to the confined excitons in Si nanostructures and a lower lying state related with surfaces of Si wires or dots. A picture of the carrier transfer between the quantum confined state and the surface localized state has been proposed. Finally, we investigated the transient electroluminescence behaviors of Au/porous silicon/Si/Al structure and found it is very similar to that of an ordinary p-n junction light-emitting diode. The mechanism of electroluminescence is explained as the carrier injection through the Au/porous silicon Schotky barrier and the porous silicon/p-Si heterojunction into the corrugated Si wires, where the radiative recombination of carriers occurs.

N-Type Silicon Films Produced by Hot Wire Technique

2000 ◽  
Vol 609 ◽  
Author(s):  
Isabel M. M. Ferreira ◽  
Ana M. F. Cabrita ◽  
Elvira M. C. Fortunato ◽  
Rodrigo F. P. Martins
Keyword(s):  
Pressure Range ◽  
Chemical Vapour ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Large Area ◽  
Deposition Pressure ◽  
Hydrogen Dilution ◽  
Exponential Increase ◽  
Sims Analysis

ABSTRACTThe role of the deposition pressure (p) and the type of filaments (tungsten, W or tantalum, Ta) used to produce large area (10cm×10cm) n-type Si:H films by hot wire chemical vapour (HW-CVD) deposition technique was investigated. The data show that the electro-optical properties of the films produced are dependent on the gas pressure used. In the pressure range of 1×10-3 Torr to 1.0 Torr, the room dark conductivity (σd) varies from 1×10-8 to 2 S/cm for films produced at the same hydrogen dilution and filament temperature (Tfil.). On the other hand, the hydrogen concentration (CH) decreases from 10% to 2%, while the growth rate (R) shows an exponential increase, from 1 to 9 Å/s. The SIMS analysis, within the detection limits, does not reveal the existence of any significant W or Ta contamination in the films produced.

Thermal and optical applications of thin film diamond

1993 ◽  
Vol 342 (1664) ◽  
pp. 313-322 ◽  
Keyword(s):  
Natural Diamond ◽  
Chemical Vapour ◽  
Wide Band ◽  
Cvd Diamond ◽  
Market Potential ◽  
Heat Sinks ◽  
Diamond Growth ◽  
Large Area ◽  
X Ray ◽  
Optical Applications

Virtually all recent reviews of the market potential for chemical vapour deposited (CVD) diamond have featured the thermal management of electronic semiconductor devices as an imminent application for this new material. There is an existing market for natural diamond substrates (‘heat sinks’) in sub-millimetre sizes, and their thermal performance has been extensively studied, CVD diamond heat sinks in millimetre and larger sizes are already in use, but there are constraints to their applicability arising from thermal and mechanical factors. Their advantages and limitations are discussed. The first ‘optical’ applications of CVD diamond films were as X-ray transmissive components (lithography masks and windows for soft X-ray detectors), but with improvements in the technology of CVD diamond growth a larger market for wide-band infrared transmissive windows is now developing. This results from the availability of large area (greater than 1000 mm 2 ) CVD diamond plates of adequate thickness and with transparency achieved through control of diamond grain size and orientation.

The critical role of the coordination sphere in the high-efficiency blue-light emission from aminopyrazine metal-organic polymers

2021 ◽  
Vol 186 ◽  
pp. 109025
Author(s):  
João Humberto Dias Campos ◽  
Meiry Edivirges Alvarenga ◽  
Maykon Alves Lemes ◽  
José Antônio do Nascimento Neto ◽  
Freddy Fernandes Guimarães ◽  
...  
Keyword(s):  
Blue Light ◽  
Coordination Sphere ◽  
High Efficiency ◽  
Light Emission ◽  
Critical Role ◽  
Organic Polymers ◽  
Blue Light Emission ◽  
Metal Organic

scholarly journals An Automatic Offset Calibration Method for Differential Charge-Based Capacitance Measurement

2021 ◽  
Vol 11 (2) ◽  
pp. 22
Author(s):  
Umberto Ferlito ◽  
Alfio Dario Grasso ◽  
Michele Vaiana ◽  
Giuseppe Bruno
Keyword(s):  
Standard Deviation ◽  
Output Voltage ◽  
Process Variations ◽  
Calibration Method ◽  
Capacitance Measurement ◽  
Effective Technique ◽  
Fully Integrated ◽  
Front End ◽  
Novel Method ◽  
On Chip

Charge-Based Capacitance Measurement (CBCM) technique is a simple but effective technique for measuring capacitance values down to the attofarad level. However, when adopted for fully on-chip implementation, this technique suffers output offset caused by mismatches and process variations. This paper introduces a novel method that compensates the offset of a fully integrated differential CBCM electronic front-end. After a detailed theoretical analysis of the differential CBCM topology, we present and discuss a modified architecture that compensates mismatches and increases robustness against mismatches and process variations. The proposed circuit has been simulated using a standard 130-nm technology and shows a sensitivity of 1.3 mV/aF and a 20× reduction of the standard deviation of the differential output voltage as compared to the traditional solution.

scholarly journals Nanofabrication using home-made RF plasma coupled chemical vapour deposition system

2014 ◽  
Vol 32 ◽  
pp. 1460342
Author(s):  
Si Ci Ong ◽  
Usman Ilyas ◽  
Rajdeep Singh Rawat
Keyword(s):  
Chemical Vapour ◽  
Chemical Vapor ◽  
Wide Band ◽  
Zno Nanowires ◽  
Operating Conditions ◽  
Rf Plasma ◽  
Zno Nanostructures ◽  
Energetic Ions ◽  
Cvd Method ◽  
Etching Effect

Zinc oxide, ZnO , a popular semiconductor material with a wide band gap (3.37 eV) and high binding energy of the exciton (60 meV), has numerous applications such as in optoelectronics, chemical/biological sensors, and drug delivery. This project aims to (i) optimize the operating conditions for growth of ZnO nanostructures using the chemical vapor deposition (CVD) method, and (ii) investigate the effects of coupling radiofrequency (RF) plasma to the CVD method on the quality of ZnO nanostructures. First, ZnO nanowires were synthesized using a home-made reaction setup on gold-coated and non-coated Si (100) substrates at 950 °C. XRD, SEM, EDX, and PL measurements were used for characterizations and it was found that a deposition duration of 10 minutes produced the most well-defined ZnO nanowires. SEM analysis revealed that the nanowires had diameters ranging from 30-100 mm and lengths ranging from 1-4 µm. In addition, PL analysis showed strong UV emission at 380 nm, making it suitable for UV lasing. Next, RF plasma was introduced for 30 minutes. Both remote and in situ RF plasma produced less satisfactory ZnO nanostructures with poorer crystalline structure, surface morphology, and optical properties due to etching effect of energetic ions produced from plasma. However, a reduction in plasma discharge duration to 10 minutes produced thicker and shorter ZnO nanostructures. Based on experimentation conducted, it is insufficient to conclude that RF plasma cannot aid in producing well-defined ZnO nanostructures. It can be deduced that the etching effect of energetic ions outweighed the increased oxygen radical production in RF plasma nanofabrication.

scholarly journals Light Emission from Rare-Earth Doped Silicon Nanostructures

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
J. Li ◽  
O. H. Y. Zalloum ◽  
T. Roschuk ◽  
C. L. Heng ◽  
J. Wojcik ◽  
...  
Keyword(s):  
Rare Earth ◽  
Electron Cyclotron Resonance ◽  
Light Emission ◽  
Chemical Vapour ◽  
Annealing Conditions ◽  
Lighting Conditions ◽  
Deposition Parameters ◽  
Doped Silicon ◽  
Rare Earth Doped ◽  
Resonance Plasma

Rare earth (Tb or Ce)-doped silicon oxides were deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). Silicon nanocrystals (Si-ncs) were formed in the silicon-rich films during certain annealing processes. Photoluminescence (PL) properties of the films were found to be highly dependent on the deposition parameters and annealing conditions. We propose that the presence of a novel sensitizer in the Tb-doped oxygen-rich films is responsible for the indirect excitation of the Tb emission, while in the Tb-doped silicon-rich films the Tb emission is excited by the Si-ncs through an exciton-mediated energy transfer. In the Ce-doped oxygen-rich films, an abrupt increase of the Ce emission intensity was observed after annealing at 1200∘C. This effect is tentatively attributed to the formation of Ce silicate. In the Ce-doped silicon-rich films, the Ce emission was absent at annealing temperatures lower than 1100∘C due to the strong absorption of Si-ncs. Optimal film compositions and annealing conditions for maximizing the PL intensities of the rare earths in the films have been determined. The light emissions from these films were very bright and can be easily observed even under room lighting conditions.

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