scholarly journals Dielectric Response of ZnTe–Ti/Al Schottky Junctions with CdTe Quantum Dots Studied by Impedance Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 170
Author(s):  
Eunika Zielony ◽  
Ewa Płaczek-Popko ◽  
Grzegorz Karczewski
Keyword(s):  
Activation Energy ◽  
Quantum Dots ◽  
Impedance Spectroscopy ◽  
Quantum Dot ◽  
Electric Modulus ◽  
Deep Level ◽  
Reference Sample ◽  
Relaxation Processes ◽  
Zero Bias ◽  
Schottky Junctions

The electrical properties of ZnTe–Ti/Al Schottky junctions were investigated by the impedance spectroscopy (IS) method. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were also performed. The studied samples were the CdTe quantum dot structures embedded in ZnTe matrix and a reference ZnTe sample without quantum dots. C-V characteristics confirmed the presence of quantum dots (QDs) in the structures. Electric modulus and impedance data were analyzed. IS studies proved that long-range conductivity governs the relaxation processes in the junctions. For both samples, the data were fitted with a simple RC circuit composed of a depletion layer capacitance in parallel with bulk resistance and a series resistance of contacts. The activation energy of the relaxation process observed for the reference sample obtained from the Arrhenius plot of the resistance, imaginary impedance, and electric modulus equals 0.4 eV at zero bias. For the quantum dot sample, the value of activation energy determined with the help of the same methods equals 0.2 eV. In conclusion, it was assumed that the relaxation processes for the reference sample are attributed to the trap present in ZnTe host material, whereas those observed for the QD structure are assigned to the deep level associated with defects located close to the QDs created during their growth.

Kinetics of Hydrogen Motion via Dislocation Network in Hydrophilically Direct Bonded Silicon Wafers

2013 ◽  
Vol 205-206 ◽  
pp. 341-345 ◽  
Author(s):  
A.S. Loshachenko ◽  
Oleg F. Vyvenko ◽  
Oleg Kononchuk
Keyword(s):  
Activation Energy ◽  
Deep Level ◽  
Total Concentration ◽  
Reference Sample ◽  
Dislocation Network ◽  
Hydrogen Penetration ◽  
Wet Chemical ◽  
Transient Spectroscopy ◽  
Hydrogen Bound ◽  
Kinetics Of

The kinetics of hydrogen penetration through dislocation networks produced by silicon wafer bonding are investigated by means of reverse bias annealing (RBA) procedure. By using the combination of capacitance-voltage (CV) profiling of net-acceptor concentration and deep level transient spectroscopy (DLTS) the total concentration of H introduced in the samples during wet–chemical etching at room temperature was defined. Two processes with the different time constants τ1and τ2was found for the bonded sample. The slow process τ1with an activation energy of (1.25±0.13) eV was analogous to that in the reference sample and corresponded to the dissociation of boron-hydrogen pairs. The fast process τ2was found to exhibit a lower activation energy of (0.87±0.25) eV and was identified as the release of hydrogen bound at screw dislocations by their elastic strains.

scholarly journals Transport signatures of an Andreev molecule in a quantum dot–superconductor–quantum dot setup

2019 ◽  
Vol 10 ◽  
pp. 363-378 ◽  
Author(s):  
Zoltán Scherübl ◽  
András Pályi ◽  
Szabolcs Csonka
Keyword(s):  
Quantum Dots ◽  
Quantum Information ◽  
Quantum Dot ◽  
Cooper Pair ◽  
Differential Conductance ◽  
Zero Bias ◽  
Local Mechanism ◽  
Special Cases ◽  
Non Local ◽  
Hybrid Devices

Hybrid devices combining quantum dots with superconductors are important building blocks of conventional and topological quantum-information experiments. A requirement for the success of such experiments is to understand the various tunneling-induced non-local interaction mechanisms that are present in the devices, namely crossed Andreev reflection, elastic co-tunneling, and direct interdot tunneling. Here, we provide a theoretical study of a simple device that consists of two quantum dots and a superconductor tunnel-coupled to the dots, often called a Cooper-pair splitter. We study the three special cases where one of the three non-local mechanisms dominates, and calculate measurable ground-state properties, as well as the zero-bias and finite-bias differential conductance characterizing electron transport through this device. We describe how each non-local mechanism controls the measurable quantities, and thereby find experimental fingerprints that allow one to identify and quantify the dominant non-local mechanism using experimental data. Finally, we study the triplet blockade effect and the associated negative differential conductance in the Cooper-pair splitter, and show that they can arise regardless of the nature of the dominant non-local coupling mechanism. Our results should facilitate the characterization of hybrid devices, and their optimization for various quantum-information-related experiments and applications.

Investigation of Dielectric Properties, Electric Modulus and Conductivity of the Au/Zn-Doped PVA/n-4H-SiC (MPS) Structure Using Impedance Spectroscopy Method

2020 ◽  
Vol 234 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Havva Elif Lapa ◽  
Ali Kökce ◽  
Ahmet Faruk Özdemir ◽  
Şemsettin Altındal
Keyword(s):  
Impedance Spectroscopy ◽  
Electric Modulus ◽  
Forward Bias ◽  
Spectroscopy Method ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Low Frequencies ◽  
High Frequencies ◽  
The Real ◽  
Wide Range

AbstractThe 50 nm thickness Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC semiconductor as interlayer by electro-spinning method and so Au/Zn-doped PVA/n-4H-SiC metal-polymer-semiconductor (MPS) structure were fabricated. The real and imaginary parts of the complex dielectric constant (ε′, ε′′), loss-tangent (tan δ), the real and imaginary parts of the complex electric modulus (M′, M′′) and ac electrical conductivity (σac) behavior of this structure were examined using impedance spectroscopy method in a wide range of frequency (1 kHz–400 kHz) and voltage (−1 V)–(+6 V) at room temperature. The values of ε′, ε′′, tan δ, M′, M′′ and σac are determined sensitive to the frequency and voltage in depletion and accumulation regions. The values of ε′ and ε′′ decrease with increasing frequency while the values of M′ and σac increase. The peak behavior in the tan δ and M′′ vs. frequency curves was attributed to the dielectric relaxation processes and surface states (Nss). The plots of ln (σac) vs. ln (f) at enough high forward bias voltage (+6 V) have three linear regions with different slopes which correspond to low, intermediate and high frequencies, respectively. The dc conductivity is effective at low frequencies whereas the ac conductivity effective at high frequencies. According to experimental results, the surface/dipole polarizations can occur more easily occur at low frequencies and the majority of Nss between Zn-doped PVA and n-4H-SiC contributes to the deviation of dielectric behavior of this structure.

Direct Observation of Polarons in Electron Populated Quantum Dots by Resonant Raman Scattering

2008 ◽  
Vol 8 (2) ◽  
pp. 789-794 ◽  
Author(s):  
B. Aslan ◽  
H. C. Liu ◽  
M. Korkusinski ◽  
P. Hawrylak ◽  
D. J. Lockwood
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Direct Observation ◽  
Physical Nature ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Relaxation Processes ◽  
Solid State Physics ◽  
Coupled Modes ◽  
Resonant Raman

The general problem of the pairing of strongly interacting elementary excitations producing new quasiparticles such as polarons arises in many areas of solid state physics. Recent interest in polaron formation in semiconductor quantum dots has been motivated by the need to understand the physical nature of the carrier relaxation processes and their role in quantum-dot based devices. We report on the direct observation of polarons in InAs/GaAs self-assembled quantum dots populated by few electrons where the polarons are strongly coupled modes of quantum dot phonons and electron intersublevel transitions. The degree of coupling is varied in a systematic way in a set of samples having electron intersublevel spacing changing from larger to smaller than the longitudinal optical phonon energy. The signature of polarons is evidenced clearly by the observation of a large (12–20 meV) anticrossing for both InAs and GaAs-like quantum dot phonons using resonant Raman spectroscopy.

Activation energy of relaxation processes in chalcogenide glasses

2013 ◽  
Vol 34 (0) ◽  
pp. 59-63
Author(s):  
А. А. Горват ◽  
В. М. Кришеник ◽  
А. Е. Кріштофорій ◽  
В. В. Мінькович ◽  
О. А. Молнар
Keyword(s):  
Activation Energy ◽  
Chalcogenide Glasses ◽  
Relaxation Processes

EXPERIMENTAL VERIFICATION OF DLTS MODELS

2019 ◽  
Author(s):  
Nataliya Mitina ◽  
Vladimir Krylov
Keyword(s):  
Activation Energy ◽  
Gallium Arsenide ◽  
Data Processing ◽  
Experimental Verification ◽  
Deep Level ◽  
Deep Levels ◽  
Transient Spectroscopy

The results of an experiment to determine the activation energy of a deep level in a gallium arsenide mesastructure, obtained by the method of capacitive deep levels transient spectroscopy with data processing according to the Oreshkin model and Lang model, are considered.

DEEP LEVELS' ACTIVATION ENERGY DEPENDENCE ON MEASUREMENT MODES

2019 ◽  
Author(s):  
Aleksey Bogachev ◽  
Vladimir Krylov
Keyword(s):  
Activation Energy ◽  
Gallium Arsenide ◽  
Energy Dependence ◽  
Deep Level ◽  
Deep Levels ◽  
Blocking Voltage

The results of an experiment to determine the activation energy of a deep level in a gallium arsenide mesastructure by capacitive relaxation spectroscopy of deep levels at various values of the blocking voltage are considered.

NiAg-graphene quantum dot-graphene hybrid with high oxidase-like catalytic activity for sensitive colorimetric detection of malathion

2021 ◽  
Author(s):  
Xu Dan ◽  
Ruiyi Li ◽  
Qinsheng Wang ◽  
Yongqiang Yang ◽  
Haiyan Zhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Quantum Dot ◽  
Colorimetric Detection ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Graphene Quantum Dot ◽  
Nickel Silver

The paper reports the synthesis of nickel-silver-graphene quantum dot-graphene hybrid. Histidine-functionalized graphene quantum dots (His-GQDs) were bonded to graphene oxide (GO) and then combined with Ni2+ and Ag+ to form...

scholarly journals Effect of Growth Temperature on the Characteristics of CsPbI3-Quantum Dots Doped Perovskite Film

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4439
Author(s):  
Shui-Yang Lien ◽  
Yu-Hao Chen ◽  
Wen-Ray Chen ◽  
Chuan-Hsi Liu ◽  
Chien-Jung Huang
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Quantum Dots ◽  
Quantum Dot ◽  
Growth Temperature ◽  
Electron Mobility ◽  
Surface Defects ◽  
Different Temperatures ◽  
Pb Doping ◽  
Pristine Film

In this study, adding CsPbI3 quantum dots to organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a doped perovskite film filmed by different temperatures was found to effectively reduce the formation of unsaturated metal Pb. Doping a small amount of CsPbI3 quantum dots could enhance thermal stability and improve surface defects. The electron mobility of the doped film was 2.5 times higher than the pristine film. This was a major breakthrough for inorganic quantum dot doped organic perovskite thin films.

scholarly journals Topological isoconductance signatures in Majorana nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. S. Ricco ◽  
J. E. Sanches ◽  
Y. Marques ◽  
M. de Souza ◽  
M. S. Figueira ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Spin Polarization ◽  
Bound States ◽  
Spin Asymmetry ◽  
Experimental Protocol ◽  
Zero Bias ◽  
Topological Superconductor ◽  
Hybrid Device ◽  
Majorana Bound States

AbstractWe consider transport properties of a hybrid device composed by a quantum dot placed between normal and superconducting reservoirs, and coupled to a Majorana nanowire: a topological superconducting segment hosting Majorana bound states (MBSs) at the opposite ends. It is demonstrated that if highly nonlocal and nonoverlapping MBSs are formed in the system, the zero-bias Andreev conductance through the dot exhibits characteristic isoconductance profiles with the shape depending on the spin asymmetry of the coupling between the dot and the topological superconductor. Otherwise, for overlapping MBSs with less degree of nonlocality, the conductance is insensitive to the spin polarization and the isoconductance signatures disappear. This allows to propose an alternative experimental protocol for probing the nonlocality of the MBSs in Majorana nanowires.

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