9 research outputs found
Investigation of the Effects of the Multiplication Area Shape on the Operational Parameters of InGaAs/InAlAs SPADs
A 2D model of an InGaAs/InAlAs single photon avalanche photodiode has been
developed. The influence of the active area structure in the multiplication
region on the diode's operating parameters has been studied. It was found that
changing the diameter of the structure's active region leads to a change in the
dark current in the linear part of the current-voltage curve and a change in
the breakdown voltage. Reducing the diameter of the active region from 25
m to 10 m allowed decreasing the dark current in the linear mode by
about dB. It has been shown that the quality of the SPAD device can be
assessed by knowing the avalanche breakdown voltage and the overall
current-voltage curve plot if we consider structures with the same
multiplication region thickness and different remaining layers. The higher the
breakdown voltage, the better the structure's quality due to smaller local
increases in the field strength. Following this statement, we conclude that for
further use in single-photon detectors, it is reasonable to pick specific SPADs
from a batch on the sole basis of their current-voltage curves
Equivalence principle and experimental tests of gravitational spin effects
We study the possibility of experimental testing the manifestations of
equivalence principle in spin-gravity interactions. We reconsider the earlier
experimental data and get the first experimental bound on anomalous
gravitomagnetic moment. The spin coupling to the Earth's rotation may also be
explored at the extensions of neutron EDM and g-2 experiments. The spin
coupling to the terrestrial gravity produces a considerable effect which may be
discovered at the planned deuteron EDM experiment. The Earth's rotation should
also be taken into account in optical experiments on a search for axionlike
particles.Comment: 12 pages, version to appear in Physical Review
Dead time duration and active reset influence on the afterpulse probability of InGaAs/InP SPAD based SPDs
We perform the detailed study of the afterpulse probability's dependence in
the InGaAs/InP sine-gated SPAD on the dead time and the used approach for its
implementation. We have found that the comparator's simple latching can
significantly reduce afterpulses' probability, even without using a dead time
pulse that lowers the diode bias voltage. We have found that with a low
probability of afterpulse ( 10 mus), it
is sufficient to use a circuit with latching of the comparator, which will
significantly simplify the development of an SPD device for applications in
which such parameters are acceptable. We also proposed a precise method for
measuring and the afterpulse and presented a model describing the recurrent
nature of this effect. We have shown that it should not use a simple model to
describe the afterpulse probability due to rough underlying physical processes.
A second-order model is preferable
Current states and superconductivity
The work is aimed at constructing the theory of current states, studying into relationship between dielectric correlations and superconductivity. Description of a new type of magnetoordered crystals - toroid magnetics - is given. A model of abnormally heavy diamagnetism of non-homogeneous toroidal magnetics is proposed. The model of separation into phases induced by superconductivity is constructed. Interzone model of electronic mechanism of superconductivity in the vicinity of the dielectric instability point is proposedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio
Non-Hermitian Hamiltonians and Quantum Transport in Multi-Terminal Conductors
We study the transport properties of multi-terminal Hermitian structures within the non-equilibrium Green’s function formalism in a tight-binding approximation. We show that non-Hermitian Hamiltonians naturally appear in the description of coherent tunneling and are indispensable for the derivation of a general compact expression for the lead-to-lead transmission coefficients of an arbitrary multi-terminal system. This expression can be easily analyzed, and a robust set of conditions for finding zero and unity transmissions (even in the presence of extra electrodes) can be formulated. Using the proposed formalism, a detailed comparison between three- and two-terminal systems is performed, and it is shown, in particular, that transmission at bound states in the continuum does not change with the third electrode insertion. The main conclusions are illustratively exemplified by some three-terminal toy models. For instance, the influence of the tunneling coupling to the gate electrode is discussed for a model of quantum interference transistor. The results of this paper will be of high interest, in particular, within the field of quantum design of molecular electronic devices