DIAGNOSIS OF SEMICONDUCTOR HETEROSYSTEMS USING THE PHOTOVOLTAIC METHOD

2021 ◽  
Vol 56 ◽  
pp. 129-133
Author(s):  
L. V. Shekhovtsov ◽  
Keyword(s):  
Potential Barrier ◽  
Transition Layer ◽  
Small Amplitude ◽  
Diagnostic Method ◽  
Photovoltaic Effect ◽  
Nitrogen Concentration ◽  
Spectral Characteristics ◽  
Schottky Contact ◽  
Semiconductor Layer ◽  
Significant Characteristic

The diagnostic method is as follows: the lateral photo-EMF spectral characteristics are measured, generated in the structure (or device) when illuminated by wavelength light with a near the edge of the basic semiconductor layer. For illustrations of efficiency method the given part of the measurement results for Schottky contact samples with a nitrogen concentration of 5% and a thermal annealing temperature of 900 and 950°C. It has been found that a significant character and a small amplitude of such a characteristic indicates qualitative at a homogeneity and the necessary magnitude of the potential barrier (or barriers), that it is necessary to form to make Schottky contact or other structure. A significant characteristic and a small amplitude of such a characteristic indicates a qualitative one-line and the required value of a potential barrier (or barriers) that must be formed for the manufacture of a semiconductor structure or device. If the spectral characteristic has one maximum and amplitude that is many times higher than the amplitude of a significant characteristic, then this indicates a formed transition layer between components of heterosystems with high, compared with a quasine-power region of semiconductor, conductivity. The presence of such a layer increases the probability breaks down of the microelectronic device. Investigation of the distribution of lateral photours along the metal semiconductor interface compliant interpretation of spectral characteristics features. The linear significant form of distribution of EMF confirms the presence of a transition layer with a lower doping level compared with GaAs. An important feature of the diagnostic method is its non-destructive character, as well as the possibility of applying to semiconductor or devices based on them, in which the photovoltaic effect may occur.

FEATURES STUDIES OF TRANSITION LAYERS IN SEMICONDUCTOR HETEROSYSTEMS

2021 ◽  
Vol 56 ◽  
pp. 108-114
Author(s):  
L. V. Shekhovtsov ◽  
Keyword(s):  
Transition Layer ◽  
Annealing Temperature ◽  
Spectral Characteristics ◽  
Schottky Contact ◽  
Charge Carriers ◽  
Point Change ◽  
Transition Layers ◽  
Equilibrium Charge ◽  
Significant Characteristic ◽  
Semiconductor Contact

Studies of spectral characteristics in Schottky's contact specimens showed that photemf generated by mono­chromatic light, according to the formation mechanism, has a predominantly lateral nature, that is, in a hetero­system there are at least two areas separated by a potential barrier along the interface, with different conductivity levels. The feature of the photoemf spectral characteristics is a variations its appearance when changing the thermal annealing temperature of the studied heterosystems. A significant characteristic and a small amplitude of the characteristic indicates the formation of a transition layer, relatively homogeneous and with insignificant, compared with the volume of GaAs, the doping concentration. If the spectral characteristic has one maximum and amplitude, which several times exceeds the amplitude of a significant characteristic, which means the formation of a transition layer in the Schottky contact depletion area with high conductivity, compared with a quasine-neutral region of a semiconductor. The distribution of lateral photoemf along the sample also has a significant character. In order to obtain the correct results relative to the heterosystem transition layer, it is necessary to measure spectral acute characteristics at a distance from the point change sign of the emf that several times the diffusion length of non-equilibrium charge carriers in GaAs. The problem of the formation of a metal-semiconductor contact and other heterosystems accompanied by the occurrence of heterogeneous transition layers, always paid attention. The use of the proposed photovoltaic method allows to establish the degree of homogeneity of semiconductor layers, components of the structure and predict the redistribution of current density flowing through the physical scope of the device.

HETEROINTERFACE PROPERTIES OF NOVEL HYBRID SOLAR CELLS CONSISTING OF TRANSPARENT CONDUCTIVE POLYMERS AND III-NITRIDE SEMICONDUCTOR

2010 ◽  
Vol 19 (04) ◽  
pp. 703-711 ◽  
Author(s):  
NOBUYUKI MATSUKI ◽  
YOSHITAKA NAKANO ◽  
YOSHIHIRO IROKAWA ◽  
MASATOMO SUMIYA
Keyword(s):  
Solar Cells ◽  
Schottky Contact ◽  
Conductive Polymer ◽  
Open Circuit ◽  
Semiconductor Layer ◽  
Clear Correlation ◽  
Hybrid Solar Cells ◽  
Specific Frequency ◽  
Rapid Drop

We have investigated the heterointerface properties of recently developed hybrid solar cells comprising a Schottky contact made of transparent conductive polymer (TCP) and an underlying GaN semiconductor layer. The heterointerface capacitance induced by the depletion layer under the TCP Schottky contact showed a rapid drop at a specific frequency. An intrinsic capacitance component that was derived from the capacitance–frequency (C–f) characteristics of the heterointerface showed clear correlation with the open circuit voltage. Hence, the C–f characterization using TCP Schottky contacts is indicative of the quality of the heterointerface.

scholarly journals Characteristic of Oral Squamous Cell Carcinoma Tissues Using Isotope Ratio Mass Spectrometry

2020 ◽  
Vol 9 (11) ◽  
pp. 3760
Author(s):  
Katarzyna Bogusiak ◽  
Aleksandra Puch ◽  
Radosław Mostowski ◽  
Marcin Kozakiewicz ◽  
Piotr Paneth ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Squamous Cell Carcinoma ◽  
Oral Mucosa ◽  
Squamous Cell ◽  
Isotope Ratio ◽  
Cancer Biology ◽  
Diagnostic Method ◽  
Nitrogen Concentration ◽  
Isotope Ratio Mass Spectrometry ◽  
Squamous Cell Carcinomas

Overall prognosis for patients with oral squamous cell carcinomas (OSSC) is still unfavourable. However, there is a hope that a novel diagnostic method may establish better cancer biology characteristics. The aim of this study was to evaluate the isotope ratio of nitrogen and carbon in OSSC as compared to margin and healthy tissue. A total of 18 patients with OSSC were included in the study. Specimens collected covered: four tumour, four margin and two healthy oral mucosa samples. The samples underwent further procedures: lyophilization and isotope ratio mass spectrometry. Measurements of the ratio of stable isotopes of nitrogen 15N/14N and carbon 13C/12C were performed. It is noticeable that the highest average nitrogen concentration was observed in tumour 12 ± 0.4% and the lowest in healthy tissues 8 ± 0.9% (p < 0.00001). The highest average carbon content was observed in healthy tissues 57 ± 2.2% and the lowest in tumour 46 ± 1.3% (p < 0.00001). Moreover, values of 15N/14N expressed in delta notation were the highest in healthy tissues 9.84 ± 0.61 and the lowest in tumour 8.92 ± 0.58. Values of 13C/12C tended to be higher in tumour −22.2 ± 0.89 and the lowest in healthy tissues −23.7 ± 1.2. Tumour tissues differ in isotopic composition from tissues taken from margin and healthy tissues taken from distant oral mucosa.

scholarly journals Увеличение фототока Ga(In)As-субэлемента в многопереходных солнечных элементах GaInP/Ga(In)As/Ge

2019 ◽  
Vol 45 (24) ◽  
pp. 41
Author(s):  
С.А. Минтаиров ◽  
В.М. Емельянов ◽  
Н.А. Калюжный ◽  
М.З. Шварц ◽  
В.М. Андреев
Keyword(s):  
Solar Cells ◽  
Potential Barrier ◽  
Triple Junction ◽  
Theoretical Study ◽  
Short Circuit ◽  
Spectral Characteristics ◽  
Short Circuit Current ◽  
Wide Bandgap ◽  
Window Layer ◽  
Wide Gap

An experimental and theoretical study of the spectral characteristics of the Ga(In)As subcell of the GaInP/Ga(In)As/Ge triple-junction solar cells has been carried out. It is shown that the use of a wide-gap “window” layer with an optimized thickness (Ga0.51In0.49P - 100 nm, Al0.4Ga0.6As - 110 nm, Al0.8Ga0.2As - 115 nm) for the Ga(In)As subcell allows increasing its photocurrent by about 0.5 mA/cm2, replacing the material of the back potential barrier of the GaInP subcell from Al0.53In0.47P to p+-Ga0.51In0.49P or AlGaAs allows increasing the short circuit current of Ga(In)As subcell by about 0.8 mA/cm2, and the use of the wide-bandgap Ga0.51In0.49P n++-layer in the tunnel diode instead of n++-GaAs increases the photocurrent by about 1 mA/cm2.

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

RSCVn Stars in the Southern Hemisphere

1979 ◽  
Vol 46 ◽  
pp. 371-384 ◽  
Author(s):  
J.B. Hearnshaw
Keyword(s):  
Light Curve ◽  
Southern Hemisphere ◽  
Orbital Period ◽  
Binary Stars ◽  
Small Amplitude ◽  
Light Variation ◽  
Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

Microstructure studies of tungsten silicide schottky contacts on Gaas

1987 ◽  
Vol 45 ◽  
pp. 328-329
Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie
Keyword(s):  
Thermal Stability ◽  
Field Effect Transistors ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Excellent Thermal Stability ◽  
Barrier Heights ◽  
Gaas Substrates ◽  
Film Adhesion ◽  
Threshold Voltages ◽  
Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

Amplitude Distributions of Cochlear Microphonic Response to an Acoustic Sinusoid in Noise

1968 ◽  
Vol 11 (1) ◽  
pp. 63-76
Author(s):  
Donald C. Teas ◽  
Gretchen B. Henry
Keyword(s):  
Small Amplitude ◽  
Basilar Membrane ◽  
Spectral Composition ◽  
Pass Band ◽  
Cochlear Microphonic ◽  
Filter Output ◽  
Electronic Filter ◽  
Low Pass ◽  
Band Pass ◽  
Instantaneous Voltage

The distributions of instantaneous voltage amplitudes in the cochlear microphonic response recorded from a small segment along the basilar membrane are described by computing amplitude histograms. Comparisons are made between the distributions for noise and for those after the addition to the noise of successively stronger sinusoids. The amplitudes of the cochlear microphonic response to 5000 Hz low-pass noise are normally distributed in both Turn I and Turn III of the guinea pig’s cochlea. The spectral composition of the microphonic from Turn I and from Turn III resembles the output of band-pass filters set at about 4000 Hz, and about 500 Hz, respectively. The normal distribution of cochlear microphonic amplitudes for noise is systematically altered by increasing the strength of the added sinusoid. A decrease of three percent in the number of small amplitude events (±1 standard deviation) in the cochlear microphonic from Turn III is seen when the rms voltage of a 500 Hz sinusoid is at −18 dB re the rms voltage of the noise (at the earphone). When the rms of the sinusoid and noise are equal, the decrease in small voltages is about 25%, but there is also an increase in the number of large voltage amplitudes. Histograms were also computed for the output of an electronic filter with a pass-band similar to Turn III of the cochlea. Strong 500 Hz sinusoids showed a greater proportion of large amplitudes in the filter output than in CM III . The data are interpreted in terms of an anatomical substrate.

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