scholarly journals Effect of Microindentation on Electroluminescence of SiC P-I-N Junctions

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 534
Author(s):  
Tingwei Zhang ◽  
Adrian H. Kitai
Keyword(s):  
Silicon Carbide ◽  
Light Source ◽  
Ideality Factor ◽  
Light Flux ◽  
Mechanical Damage

The influence of microindentation on the electroluminescence of silicon carbide was studied in forward-biased 4H SiC p-i-n junctions. Four spectral regions at approximately 390, 420, 445 and 500 nm initially observed on virgin samples strongly depend, in regard to magnitude, on the condition of the starting die. These spectral regions may be interpreted as arising from either phonon-assisted band-to-band transitions or from defect-related transitions. The same SiC die were then subjected to mechanical damage brought about by a series of closely spaced microindentations directed approximately perpendicular to the c-axis. The spectra taken after a first set and subsequently a second set of microindentations are distinct from the initial spectra in all cases, and differences are interpreted as being due to the modification of existing defects or additional defects being generated mechanically. The influence of microindentation on the ideality factor is measured and discussed. Measured light flux with respect to a standard light source is also shown at each microindentation stage.

scholarly journals Elimination of the blinding effect in landscape luminaires

2018 ◽  
Vol 7 (2.13) ◽  
pp. 252
Author(s):  
Albert Ashryatov ◽  
Dinara Churakova
Keyword(s):  
Light Curve ◽  
Light Source ◽  
Light Flux ◽  
Light Distribution ◽  
Light Sources ◽  
Mirror Surface ◽  
Light Emitting ◽  
Lighting Technology ◽  
Initial Task ◽  
Flat Beam

The article presents one of the possible options for implementing the lighting technology "Flat beam" for landscape lighting purposes. One of the possible ways to control the light distribution of a number of light sources based on LEDs with different radiation patterns is considered. As a secondary optics, it is proposed to use a mirror surface that redistributes the light flux of an LED light source. It is indicated that, depending on the initial type of the light-emitting diodes light curve and the features of mounting the mirror surface, the resulting light distribution can vary widely, depending on the initial task that the designer sets for himself.  

scholarly journals Prior Compensation Algorithm for Cerenkov Luminescence Tomography From Single-View Measurements

2021 ◽  
Vol 11 ◽  
Author(s):  
Lin Wang ◽  
Xiaowei He ◽  
Jingjing Yu
Keyword(s):  
Light Source ◽  
Imaging System ◽  
Three Dimensional ◽  
Light Flux ◽  
System Matrix ◽  
Full Account ◽  
Single View ◽  
Compensation Algorithm ◽  
Detection Plane ◽  
Calibration Matrix

Cerenkov luminescence tomography (CLT) has attracted much attention because of the wide clinically-used probes and three-dimensional (3D) quantification ability. However, due to the serious morbidity of 3D optical imaging, the reconstructed images of CLT are not appreciable, especially when single-view measurements are used. Single-view CLT improves the efficiency of data acquisition. It is much consistent with the actual imaging environment of using commercial imaging system, but bringing the problem that the reconstructed results will be closer to the animal surface on the side where the single-view image is collected. To avoid this problem to the greatest extent possible, we proposed a prior compensation algorithm for CLT reconstruction based on depth calibration strategy. This method takes full account of the fact that the attenuation of light in the tissue will depend heavily on the depth of the light source as well as the distance between the light source and the detection plane. Based on this consideration, a depth calibration matrix was designed to calibrate the attenuation between the surface light flux and the density of the internal light source. The feature of the algorithm was that the depth calibration matrix directly acts on the system matrix of CLT reconstruction, rather than modifying the regularization penalty items. The validity and effectiveness of the proposed algorithm were evaluated with a numerical simulation and a mouse-based experiment, whose results illustrated that it located the radiation sources accurately by using single-view measurements.

scholarly journals Development of portable device for measurement of dynamic and static light-emission WOLED characteristics

2021 ◽  
Vol 1 (1(57)) ◽  
pp. 30-33
Author(s):  
Ihor Helzhynsky ◽  
Stepan Kutsiy ◽  
Andriy Veryha ◽  
Khrystyna Ivaniuk ◽  
Taras Dudok
Keyword(s):  
Light Source ◽  
Data Exchange ◽  
Light Emission ◽  
Spectral Characteristics ◽  
Light Flux ◽  
Luminous Flux ◽  
Visible Range ◽  
Light Sources ◽  
Measuring Device ◽  
Routine Work

The research object of this work is the parameters of organic light-emitting diodes, namely power and luminous flux. Determination of these parameters can be carried out using a photodiode and requires measuring the dark current of the sensor (photodiode), measuring the current of the photodiode when illuminated by the LED under investigation. And also take into account the relationship between the light flux received by the sensor and its output current, and take into account the spectral characteristics of the sensor. Calculate the investigated parameters of the LED based on the measurements. Carrying out these measurements requires laboratory instruments and workplace organization, and further calculations are routine work. It is possible to increase the measurement accuracy by improving the existing methods for measuring the required parameters, and it is possible to automate the process of measurements and calculations using a modern microprocessor radioelement base. Microcontrollers are widespread such radioelements. They have the necessary peripherals for independent operation and have sufficient computing power to implement the required measuring device. Its application makes it possible to automate the measurement process, carry out the necessary calculations, save correction constants, accumulate and process the obtained data, analyze these received data, exchange data with a computer, etc. So, the work is aimed at developing a methodology that will allow the simultaneous measurement of power and luminous flux of planar light sources. And also on the feasibility of this technique in the device and software with the ability to measure the power of the light source in an arbitrary band of the spectral visible range. Thus, it is possible to determine what power in watts a light source emits with the dynamics of supply currents in the optical bands, knowing the spectrum of this source without using glass filters. So, the result of applying the technique is to determine the power of light radiation (in watts) or the luminous flux (in lumens) of the emitter (light sources).

Surface Effects of Passivation within Mo/4H-SiC Schottky Diodes through MOS Analysis

2019 ◽  
Vol 963 ◽  
pp. 511-515
Author(s):  
A. Benjamin Renz ◽  
Vishal Ajit Shah ◽  
Oliver Vavasour ◽  
Yeganeh Bonyadi ◽  
G.W.C Baker ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ideality Factor ◽  
Photoelectron Spectroscopy ◽  
Schottky Diodes ◽  
Control Sample ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
X Ray ◽  
Schottky Rectifier ◽  
Metal Oxide Semiconductor Capacitor

Passivation treatments applied prior to Mo metallisation on Silicon Carbide (SiC) Schottky rectifier and metal-oxide-semiconductor capacitor (MOSCAP) structures are studied. A control sample and two treatments, comprising of an O2 oxidation and a phosphorus pentoxide (P2O5) deposition, were studied. Electrical characterisation results show that P2O5 treatment improves the homogeneity of the diodes, with the ideality factor reducing to 1.02 and the leakage current reducing by three orders of magnitude to 2×10-5 A/cm2. Furthermore, the SBH was lowered by 0.11 eV and the variance of all the P2O5 treated Schottky characteristics over the batch reduced. Characterisation by X-ray photoelectron spectroscopy (XPS) showed that the stoichiometry, the Si:C ratio, of the SiC below the contact increased from 0.93:1 before treatment to 0.97:1 after P2O5 treatment.

scholarly journals Lifetime Prediction method of LED Light-emitting Device Based on Approximate Analysis

2021 ◽  
Vol 271 ◽  
pp. 01031
Author(s):  
Cai Wenting ◽  
Li Sheng ◽  
Meng Qinghui ◽  
Huang Haisong
Keyword(s):  
Approximate Method ◽  
Light Source ◽  
High Efficiency ◽  
Light Flux ◽  
Prediction Method ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Long Life ◽  
Application Requirements

Compared with other light sources, LED light source has a longer service life and will not suddenly fail. Due to its high efficiency, energy saving and long life, LED has become the most popular light source at present. However, it is no longer considered to meet the application requirements, and the time that the light flux decays to this level is considered to be the life of the LED. This paper introduces the approximate method used to predict the lumen maintenance life of LED lamps. The experimental results obtained by the approximate method are compared with the TM-21 standard. Eventually, it is concluded that the approximate method provides more reliability information than the original TM-21 standard, and the obtained results are more reference, more accurate and more reliable.

The Expected Performance of an Optical Pumping Light Source, and the Kinetics of Optical Pumping of 23S13He

1971 ◽  
Vol 49 (5) ◽  
pp. 525-538 ◽  
Author(s):  
J. M. Daniels ◽  
R. S. Timsit
Keyword(s):  
Angular Momentum ◽  
Light Source ◽  
Optical Pumping ◽  
Light Flux ◽  
Resonance Radiation ◽  
Transition Rates ◽  
Expected Performance ◽  
Kinetics Of

A practical light source for optical pumping necessarily excites transitions other than those which it is desired should be excited. It is shown that a pumping light source for 23S13He may be characterized by three parameters, which describe the transition rates for Δm = ±1, and 0, transitions under standard conditions. Expressions are derived relating these parameters to the geometry of the light source. The equation which describes the flow of angular momentum into 3He is formulated, using these parameters, the light flux, the lifetime of the metastable atoms, and collisional mixing in the 23P states. This equation is solved to give the polarization which may be attained, and the rate at which the polarization is built up. A modification of this equation is also given, which takes into account moderate trapping of resonance radiation. An expression is also derived which relates the polarization of 3He to the intensity of the scattered pumping light.

scholarly journals Detection of Heart and Respiration Rate with an Organic-Semiconductor-Based Optomechanical MEMS Sensor

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 715
Author(s):  
Günter Hammer ◽  
Andreas Kainz ◽  
Wilfried Hortschitz ◽  
Hsiao-Wen Zan ◽  
Hsin-Fei Meng ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Light Source ◽  
Respiration Rate ◽  
Organic Semiconductor ◽  
Light Flux ◽  
Light Distribution ◽  
Organic Optoelectronics ◽  
Mems Sensor ◽  
Sensitive Sensor ◽  
Organic Optoelectronic

We present a displacement-sensitive sensor comprising a microelectromechanical (MEMS) chip and organic optoelectronic components capable of measuring the heart and respiration rate on humans. The MEMS sensor relies on the inertial deflection of a small silicon oscillator. The readout of the deflection is optical and works via modulation of the light flux passing through the MEMS. Organic optoelectronics are used as light source and detector, since these offer a homogeneous light distribution and a more compact package in a future integration. Two types of MEMS, differing in their resonance frequency, were designed and characterised in combination with both organic and inorganic optoelectronics prior to measuring heart and respiration rate. Subsequently, by measurements on the neck, pulse and respiration rate were successfully measured.

UV-Sensitive Metal-Semiconductor Photodiodes on 6H-SIC.

1994 ◽  
Vol 339 ◽  
Author(s):  
Christer Fröjdh ◽  
Göran Thungström ◽  
Hans-Erik Nilsson ◽  
C. Sture Petersson
Keyword(s):  
Silicon Carbide ◽  
Optical Properties ◽  
Ideality Factor ◽  
Schottky Diodes ◽  
Reverse Current ◽  
Fabrication Process ◽  
Electrical And Optical Properties ◽  
Peak Sensitivity

ABSTRACTSchottky diodes on Silicon Carbide (SiC) are of interest for many applications because of the relatively simple fabrication process. In this work we have fabricated Schottky diodes by evaporation of Ti on 6H-SiC and measured their electrical and optical properties. Most of the diodes show good rectifying behaviour with low reverse current and an ideality factor below 1.20. The photoresponse of the diodes has been measured in the range 200 – 400 nm. The peak sensitivity was found to be at 270 nm.

scholarly journals Silicon carbide schottky diodes forward and reverse current properties upon fast electron radiation

2019 ◽  
Vol 8 (2) ◽  
pp. 428-437
Author(s):  
M. Azim Khairi ◽  
Rosminazuin Ab. Rahim ◽  
Norazlina Saidin ◽  
Yusof Abdullah ◽  
Nurul Fadzlin Hasbullah
Keyword(s):  
Silicon Carbide ◽  
Electron Irradiation ◽  
Ideality Factor ◽  
Reverse Bias ◽  
Series Resistance ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Bias Current ◽  
Saturation Current ◽  
Order Of Magnitude

This paper investigates on the reaction of 10 and 15MGy, 3MeV electron irradiation upon off-the-shelves (commercial) Silicon Carbide Schottky diodes from Infineon Technologies (model: IDH08SG60C) and STMicroelectronics (model: STPSC806). Such irradiation reduces the forward-bias current. The reduction is mainly due to the significant increase of the series resistance (i.e. Infineon: 1.45Ω at before irradiation → 121×103 Ω at 15MGy); STMicroelectronics: 1.44Ω at before irradiation → 2.1×109 Ω at 15MGy). This increase in series resistance gives 4.6 and 8.2 orders of magnitude reduction for the forward-bias current density of Infineon and STMicroelectronics respectively. It is also observed that the ideality factor and the saturation current of the diodes increases with increasing dose (i.e. ideality factor- Infineon: 1.01 at before irradiation → 1.05 at 15MGy; STMicroelectronics: 1.02 at before irradiation → 1.3 at 15MGy | saturation current- Infineon: 1.6×10-17A at before irradiation → 2.5×10-17A at 15MGy; STMicroelectronics: 2.4×10-15A at before irradiation → 8×10-15A at 15MGy). Reverse-bias leakage current density in model by Infineon increases by one order of magnitude after 15MGy irradiation, however, in model by STMicroelectronics decreases by one order of magnitude. Overall, for these particular samples studied, Infineon devices have shown to be better in quality and more radiation resistance toward electron irradiation in forward-bias operation while STMicroelectronics exhibit better characteristics in reverse-bias operation.

scholarly journals EFFECT OF RAPID THERMAL TREATMENT CONDITIONS ON ELECTROPHYSICAL PROPERTIES OF CROMIUM THIN FILMS ON SILICON

Doklady BGUIR ◽  
2019 ◽  
pp. 157-164 ◽  
Author(s):  
J. A. Solovjov ◽  
V. A. Pilipenko
Keyword(s):  
Thermal Treatment ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Ideality Factor ◽  
Thermal Process ◽  
Light Flux ◽  
Back Side ◽  
Rapid Thermal Process ◽  
Heating Source ◽  
Chromium Films

Present paper is devoted the determination of the effect of the temperature of the process of rapid thermal treatment of chromium films on n-type conductivity silicon on their resistivity and contact properties of the interface. Chromium films of about 30 nm thickness were deposited by magnetron sputtering onto the surface of silicon substrates having a resistivity of 0.58 to 0.53 ohms×cm. The rapid thermal treatment was carried out in a heat balance mode by irradiating the back side of the substrates with non-coherent light flux in nitrogen ambient for 7 seconds. Quartz halogen incandescent lamps were used as the heating source. The temperature of the rapid thermal process ranged from 200 to 550 °C. The thickness of the chromium films was determined by raster electron microscopy. The surface resistance of the samples was measured by a four- probe method. The Schottky barrier height and the ideality factor were determined from I-V plots. It is shown that at the temperature of the rapid thermal process 400 °C a layer of chromium disilicide is formed, causing a sharp increase in the resistivity of chromium films to 1.2 mOhm×cm and the height of the Schottky barrier to 0.6 V. When the temperature of the rapid thermal process is further increased to 550 °C, the resistivity increases monotonically to 4.0 mOhm×cm due to the increase in the width of the interstitial boundaries increasing the scattering of charge carriers in the CrSi2 layers. It has also been shown that rapid thermal treatment of the Cr/Si structure at a temperature of 450–500 °C enables to obtain rectifying contacts with a barrier height of 0.615 V and an ideality factor of 1.1. The results obtained can be used in the technology of integrated electronics products containing Schottky contacts as well as thin film resistors.

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