Высокочастотный конденсатор с рабочим веществом «изолятор нелегированный кремний изолятор»

The study of the parameters of capacitors with various working substances is of interest for the design and creation of electronic elements, in particular for the development of high-frequency phase-shifting circuits.The purpose of the work is to calculate the high-frequency capacitance of a capacitor with the working substance "insulator-undoped silicon-insulator" at different applied to the capacitor direct current (DC) voltages, measuring signal frequencies and temperatures.A model of such the capacitor is proposed, in which 30 µm thick layer of undoped (intrinsic) crystalline silicon (i-Si) is separated from each of the capacitor electrodes by 1 µm thick insulator layer (silicon dioxide).The dependences of the capacitor capacitance on the DC electrical voltage U on metal electrodes at zero frequency and at the measuring signal frequency of 1 MHz at absolute temperatures T = 300 and 400 K are calculated. It is shown that the real part of the capacitor capacitance increases monotonically, while the imaginary part is negative and non-monotonically depends on U at the temperature T = 300 K. An increase in the real part of the capacitor capacitance up to the geometric capacitance of oxide layers with increasing temperature is due to a decrease in the electrical resistance of i-Si layer. As a result, with an increase in temperature up to 400 K, the real and imaginary parts of the capacitance take constant values independent of U. The capacitance of i-Si layer with an increase in both temperature T and voltage U is shunted by the electrical conductivity of this layer. The phase shift is determined for a sinusoidal electrical signal with a frequency of 0.3, 1, 10, 30, 100, and 300 MHz applied to the capacitor at temperatures 300 and 400 K.Исследование параметров электрических конденсаторов с различными рабочими веществами представляет интерес для проектирования и создания элементов электроники, в частности для разработки высокочастотных фазосдвигающих цепей.Цель работы рассчитать высокочастотную электрическую емкость конденсатора с рабочим веществом «изолятор нелегированный кремний изолятор» при различных подаваемых на конденсатор постоянных напряжениях, частотах измерительного сигнала и температурах.Предложена модель такого конденсатора, в которой слой нелегированного (собственного) кристаллического кремния (i-Si) толщиной 30 мкм отделен от каждого из электродов конденсатора слоем изолятора (диоксида кремния) толщиной 1 мкм.Рассчитаны зависимости емкости конденсатора от постоянного электрического напряжения U на металлических электродах на нулевой частоте и на частоте измерительного сигнала 1 МГц при абсолютных температурах T = 300 и 400 К. Показано, что действительная часть емкости конденсатора монотонно возрастает, а мнимая часть отрицательна и немонотонно зависит от U при температуре T = 300 К. Увеличение действительной части емкости конденсатора до геометрической емкости оксидных слоев при увеличении температуры обусловлено уменьшением электрического сопротивления слоя i-Si. Вследствие этого с увеличением температуры до 400 К действительная и мнимая части емкости принимают постоянные значения, независящие от U. Емкость слоя i-Si при увеличении как температуры T, так и напряжения U шунтируется электрической проводимостью этого слоя. Определен сдвиг фаз для синусоидального электрического сигнала с частотой 0,3; 1; 10; 30; 100 и 300 МГц, подаваемого на конденсатор при температурах 300 и 400 К

High-Frequency Capacitor with Working Substance "Insulator–Undoped Silicon–Insulator"

The study of the parameters of capacitors with various working substances is of interest for the design and creation of electronic elements, in particular for the development of high-frequency phase-shifting circuits. The purpose of the work is to calculate the high-frequency capacitance of a capacitor with the working substance insulator undoped silicon insulator at different applied to the capacitor direct current (DC) voltages, measuring signal frequencies and temperatures. A model of such the capacitor is proposed, in which 30 µm thick layer of undoped (intrinsic) crystalline silicon (i-Si) is separated from each of the capacitor electrodes by 1 µm thick insulator layer (silicon dioxide). The dependences of the capacitor capacitance on the DC electrical voltage U on metal electrodes at zero frequency and at the measuring signal frequency of 1 MHz at absolute temperatures T = 300 and 400 K are calculated. It is shown that the real part of the capacitor capacitance increases monotonically, while the imaginary part is negative and non-monotonically depends on U at the temperature T = 300 K. An increase in the real part of the capacitor capacitance up to the geometric capacitance of oxide layers with increasing temperature is due to a decrease in the electrical resistance of i-Si layer. As a result, with an increase in temperature up to 400 K, the real and imaginary parts of the capacitance take constant values independent of U. The capacitance of i-Si layer with an increase in both temperature T and voltage U is shunted by the electrical conductivity of this layer. The phase shift is determined for a sinusoidal electrical signal with a frequency of 0.3, 1, 10, 30, 100, and 300 MHz applied to the capacitor at temperatures 300 and 400 K

Схема элемента Пельтье на полупроводниках с прыжковым переносом электронов по дефектам

The study of thermoelectric properties of crystalline semiconductors with structural defects is of practical interest in the development of radiation-resistant Peltier elements. In this case, the spectrum of energy levels of hydrogen-like impurities and intrinsic point defects in the band gap (energy gap) of crystal plays an important role.The purpose of this work is to analyze the features of the single-electron band model of semiconductors with hopping electron migration both via atoms of hydrogen-like impurities and via their own point triplecharged intrinsic defects in the c- and v-bands, as well as to search for the possibility of their use in the Peltier element in the temperature range, when the transitions of electrons and holes from impurity atoms and/or intrinsic defects to the c- and v-bands can be neglected.For Peltier elements with electron hopping migration we propose: (i) an h-diode containing |d1)and |d2)-regions with hydrogen-like donors of two types in the charge states (0) and (+1) and compensating them hydrogen-like acceptors in the charge state (−1); (ii) a homogeneous semiconductor containing intrinsic t-defects in the charge states (−1, 0, +1), as well as ions of donors and acceptors to control the distribution of t-defects over the charge states. The band diagrams of the proposed Peltier elements in equilibrium and upon excitation of a stationary hopping electric current are analyzed.A model of the h-diode containing hydrogen-like donors of two types |d1) and |d2) with hopping migration of electrons between them for 50 % compensation by acceptors is considered. It is shown that in the case of the reverse (forward) electrical bias of the diode, the cooling (heating) of the region of the electric double layer between |d1)and |d2)-regions is possible.A Peltier element based on a semiconductor with point t-defects is considered. It is assumed that the temperature and the concentration of ions of hydrogen-like acceptors and donors are to assure all t-defects to be in the charge state (0). It is shown that in such an element it is possible to cool down the metal-semiconductor contact under a negative electric potential and to heat up the opposite contact under a positive potential.Исследование термоэлектрических свойств кристаллических полупроводников с дефектами структуры представляет практический интерес при создании радиационно-стойких элементов Пельтье. При этом важную роль играет спектр уровней энергии водородоподобных примесей и собственных точечных дефектов в энергетической щели (запрещённой зоне) кристалла.Цель работы анализ особенностей одноэлектронной зонной модели полупроводников с прыжковой миграцией электронов как по атомам водородоподобных примесей, так и по собственным точечным трёхзарядным дефектам, а также поиск возможности их использования в элементе Пельтье в области температур, когда переходами электронов и дырок с атомов примесей и/или собственных дефектов в cи v-зоны можно пренебречь.В качестве элементов Пельтье с прыжковой миграцией электронов предложены: 1) h-диод, содержащий |d1)и |d2)-области с водородоподобными донорами двух сортов в зарядовых состояниях(0) и (+1) и компенсирующие их водородоподобные акцепторы в зарядовом состоянии (−1); 2) однородный полупроводник, содержащий собственные t-дефекты в зарядовых состояниях (−1, 0, +1), а также ионы доноров и акцепторов для управления распределением t-дефектов по зарядовых состояниям. Проанализированы зонные диаграммы предлагаемых элементов Пельтье в равновесии  и при возбуждении стационарного прыжкового электрического тока.Рассмотрена модель h-диода, содержащего водородоподобные доноры двух сортов |d1) и |d2) с прыжковой миграцией между ними электронов при компенсации их на 50 % акцепторами. Показано, что при обратном (прямом) электрическом смещении диода возможно охлаждение (нагревание) области двойного электрического слоя между |d1)и |d2)-областями.Рассмотрен элемент Пельтье на основе полупроводника с точечными t-дефектами. Принималось, что температура, а также концентрации ионов водородоподобных акцепторов и доноров таковы, что практически все t-дефекты находятся в зарядовом состоянии (0). Показано, что в таком элементе возможно охлаждение контакта металл-полупроводник, находящегося под отрицательным электрическим потенциалом, и нагревание противоположного контакта, под положительным потенциалом

Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector

The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV for the direct photon emission in the K- --> pi- pi0 gamma decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37+-0.39(stat)+-0.10(syst)]*10^(-5) obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.Comment: 13 pages, 8 figure

Analysis of Recombination Processes in 0.5-0.6 eV Epitaxial GaInAsSb Lattice-matched to GaSb

Abstract. This work summarizes recent data on minority carrier lifetime in n-and p-type double heterostructures (DHs) of 0.5-0.6 eV GaInAsSb confined with GaSb and AlGaAsSb cap layers. Recombination times were measured by time-resolved photoluminescence (TRPL) and by optical frequency response (OFR) to sinusoidal excitation. It was shown that one of the mechanisms responsible for interface recombination in GaSb/GaInAsSb/GaSb DHs is thermionic emission of carriers over the heterobarrier. Considerable improvement of carrier confinement was obtained with 1 eV AlGaAsSb cap layers. Optimization of the epitaxial growth resulted in a recombination velocity at GaInAsSb/AlGaAsSb interface as low as 30 cm/s

B Physics at the Tevatron: Run II and Beyond

This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.Comment: 583 pages. Further information on the workshops, including transparencies, can be found at the workshop's homepage: http://www-theory.lbl.gov/Brun2/. The report is also available in 2-up http://www-theory.lbl.gov/Brun2/report/report2.ps.gz or chapter-by-chapter http://www-theory.lbl.gov/Brun2/report

Top quark mass measurement using the template method at CDF

We present a measurement of the top quark mass in the lepton+jets and dilepton channels of $t\bar{t}$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb$^{-1}$ of $p\bar{p}$ collisions at Tevatron with $\sqrt{s}=1.96$ TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the $W$ decay in the lepton+jets channel, and a reconstructed top quark mass and $m_{T2}$, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of $M_{top} = 172.1 \pm 1.1(stat) \pm 0.9(syst).$Comment: submitted to Phys. Rev.

Observation and Mass Measurement of the Baryon Ξb−\Xi^-_b

We report the observation and measurement of the mass of the bottom, strange baryon $\Xi^-_b$ through the decay chain $\Xi^-_b \to J/\psi \Xi^-$, where $J/\psi \to \mu^+ \mu^-$, $\Xi^- \to \Lambda \pi^-$, and $\Lambda \to p \pi^-$. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard deviations. The $\Xi^-_b$ mass is measured to be $5792.9\pm 2.5$ (stat.) $\pm 1.7$ (syst.) MeV/$c^2$.Comment: Minor text changes for the second version. Accepted by Phys. Rev. Let