Electronic Properties and Density of States of Self-Assembled GaSb/GaAs Quantum Dots

The electronic properties of a self-assembled GaSb/GaAs QD ensemble are determined by capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS). The charging and discharging bias regions of the QDs are determined for different temperatures. With a value of 335 (±15) meV the localization energy is rather small compared to values previously determined for the same material system. Similarly, a very small apparent capture cross section is measured (1·10−16 cm2). DLTS signal analysis yields an equivalent to the ensemble density of states for the individual energies as well as the density function of the confinement energies of the QDs in the ensemble.

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Electronic Properties of ZnO/Si Heterojunction Prepared by ALD.

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.178-179.130 ◽

2011 ◽

Vol 178-179 ◽

pp. 130-135 ◽

Cited By ~ 4

Author(s):

Vincent Quemener ◽

Mari Alnes ◽

Lasse Vines ◽

Ola Nilsen ◽

Helmer Fjellvåg ◽

...

Keyword(s):

Electronic Properties ◽

Deep Level ◽

Atomic Layer ◽

Substantial Improvement ◽

Conduction Band Edge ◽

Energy Position ◽

Layer Deposition ◽

Current Voltage ◽

Capacitance Voltage ◽

Transient Spectroscopy

ZnO/n-Si and ZnO/p-Si heterostructures were prepared by Atomic layer deposition (ALD) and the electronic properties have been investigated by Current-Voltage (I-V), Capacitance-Voltage (C-V) and Deep level transient spectroscopy (DLTS) measurements. DLTS measurements show two dominants electron traps at the interface of the ZnO/n-Si junction with energy position at 0.07 eV and 0.15 eV below the conduction band edge, labelled E(0.07) and E(0.15), respectively, and no electrically active defects at the interface of the ZnO/p-Si junction. E(0.07) is reduced by annealing up to 400°C while E(0.15) is created at 500°C. The best heterostructure is found after heat treatment at 400°C with a substantial improvement of the current rectification for ZnO/n-Si and the formation of Ohmic contact on ZnO/p-Si. A reduction of the interface defects correlates with an improvement of the crystal structure of the ZnO film with a preferred orientation along the c-axis.

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Evolution of Electronic Properties of Cu(In, Ga)Se2 (CIGS)-Based Solar Cells During a 3-stage Growth Process

MRS Proceedings ◽

10.1557/proc-763-b5.25 ◽

2003 ◽

Vol 763 ◽

Cited By ~ 1

Author(s):

Jehad A. AbuShama ◽

S. Johnston ◽

R. Ahrenkiel ◽

R. Crandall ◽

D. Young ◽

...

Keyword(s):

Solar Cells ◽

Electronic Properties ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Thin Film Solar Cells ◽

Polycrystalline Thin Film ◽

Capacitance Voltage ◽

Carrier Traps ◽

Stage Process ◽

Transient Spectroscopy

AbstractWe investigated the electronic properties of ZnO/CdS/CIGS/Mo/SLG polycrystalline thin-film solar cells with compositions ranging from Cu-rich to In(Ga)-rich by deep-level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. This compositional change represents the evolution of the film during growth by the 3-stage process. Two sets (four samples each) of CIGS thin films were prepared with Ga/(In+Ga) ratios of ∼0.3 (low Ga) and ∼0.6 (high Ga). The Cu/(In+Ga) ratio ranges from 1.24 (Cu-rich) to 0.88 (In(Ga)-rich). The films were treated with NaCN to remove the Cu2-xSe phase where needed. Key results include: (1) For lowGa devices, DLTS data show that acceptor-like traps dominate in samples where CIGS grains do not go through the Cu-rich to In(Ga)-rich transition, whereas donor-like traps dominate in In(Ga)-rich samples. Therefore, we see a clear transformation of defects from acceptor-like to donor-like traps. The activation energies of these traps range from 0.12 to 0.63 eV. We also observed that NaCN treatment eliminates a deep minority trap in the In(Ga)-rich devices, (2) For high-Ga devices, only majority-carrier traps were detected. These traps again range from shallow to deep, (3) The carrier concentration around the junction and the density of traps decrease as the CIGS becomes more In(Ga)-rich.

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Correlation between Defects and Electrical Performances of Ion-Irradiated 4H-SiC p–n Junctions

Materials ◽

10.3390/ma14081966 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1966

Author(s):

Domenico Pellegrino ◽

Lucia Calcagno ◽

Massimo Zimbone ◽

Salvatore Di Franco ◽

Antonella Sciuto

Keyword(s):

Deep Level ◽

Electrical Characterization ◽

High Fluence ◽

Defect States ◽

Exponential Parameter ◽

Current Voltage ◽

Different Temperatures ◽

In Series ◽

Transient Spectroscopy ◽

Fluence Range

In this study, 4H-SiC p–n junctions were irradiated with 700 keV He+ ions in the fluence range 1.0 × 1012 to 1.0 × 1015 ions/cm2. The effects of irradiation were investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements, while deep-level transient spectroscopy (DLTS) was used to study the traps introduced by irradiation defects. Modifications of the device’s electrical performances were observed after irradiation, and two fluence regimes were identified. In the low fluence range (≤1013 ions/cm2), I–V characteristics evidenced an increase in series resistance, which can be associated with the decrease in the dopant concentration, as also denoted by C–V measurements. In addition, the pre-exponential parameter of junction generation current increased with fluence due to the increase in point defect concentration. The main produced defect states were the Z1/2, RD1/2, and EH6/7 centers, whose concentrations increased with fluence. At high fluence (>1013 ions/cm2), I–V curves showed a strong decrease in the generation current, while DLTS evidenced a rearrangement of defects. The detailed electrical characterization of the p–n junction performed at different temperatures highlights the existence of conduction paths with peculiar electrical properties introduced by high fluence irradiation. The results suggest the formation of localized highly resistive regions (realized by agglomeration of point defects) in parallel with the main junction.

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Deep level transient spectroscopy characterization of InAs self-assembled quantum dots

Journal of Applied Physics ◽

10.1063/1.1336519 ◽

2001 ◽

Vol 89 (2) ◽

pp. 1172-1174 ◽

Cited By ~ 26

Author(s):

V. V. Ilchenko ◽

S. D. Lin ◽

C. P. Lee ◽

O. V. Tretyak

Keyword(s):

Quantum Dots ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Self Assembled ◽

Transient Spectroscopy

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Влияние нейтронного облучения на спектр дефектов с глубокими уровнями в GaAs, изготовленном методом жидкофазной эпитаксии в атмосфере водорода и аргона

Физика и техника полупроводников ◽

10.21883/ftp.2022.01.51812.9729 ◽

2022 ◽

Vol 56 (1) ◽

pp. 53

Author(s):

М.М. Соболев ◽

Ф.Ю. Солдатенков

Keyword(s):

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Experimental Studies ◽

Shallow Donor ◽

Defect Clusters ◽

Deep Traps ◽

Capacitance Voltage ◽

Before And After ◽

Transient Spectroscopy ◽

Different Doses

The results of experimental studies of capacitance– voltage characteristics, spectra of deep-level transient spectroscopy of graded high-voltage GaAs p+−p0−i−n0 diodes fabricated by liquid-phase epitaxy at a crystallization temperature of 900C from one solution–melt due to autodoping with background impurities, in a hydrogen or argon ambient, before and after irradiation with neutrons. After neutron irradiation, deep-level transient spectroscopy spectra revealed wide zones of defect clusters with acceptor-like negatively charged traps in the n0-layer, which arise as a result of electron emission from states located above the middle of the band gap. It was found that the differences in capacitance–voltage characteristics of the structures grown in hydrogen or argon ambient after irradiation are due to different doses of irradiation of GaAs p+−p0−i−n0 structures and different degrees of compensation of shallow donor impurities by deep traps in the layers.

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Capacitance-voltage and deep-level-transient spectroscopy characterization of defects near SiO2/SiC interfaces

Journal of Applied Physics ◽

10.1063/1.3552303 ◽

2011 ◽

Vol 109 (6) ◽

pp. 064514 ◽

Cited By ~ 43

Author(s):

A. F. Basile ◽

J. Rozen ◽

J. R. Williams ◽

L. C. Feldman ◽

P. M. Mooney

Keyword(s):

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Capacitance Voltage ◽

Transient Spectroscopy

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Dlts and CV Analysis of Doped and N-Implanted GaN

MRS Proceedings ◽

10.1557/proc-423-531 ◽

1996 ◽

Vol 423 ◽

Cited By ~ 1

Author(s):

D. Haase ◽

M. Schmid ◽

A. Dörnen ◽

V. Härle ◽

H. Bolay ◽

...

Keyword(s):

Carrier Concentration ◽

Deep Level ◽

Implantation Dose ◽

Nitrogen Implantation ◽

Capacitance Voltage ◽

Defect Levels ◽

Transient Spectroscopy ◽

Additional Defect ◽

Cv Measurements ◽

Dlts Spectra

AbstractWe studied by deep level transient spectroscopy (DLTS) and capacitance-voltage (CV) measurements the effects of doping (Zn, S), nitrogen implantation and annealing of n-type GaN grown on sapphire by MOVPE. The DLTS spectra of the as grown samples show two defect levels which are assumed to be identical with recently reported levels [10, 11]. In N-implanted GaN a third level is introduced which is not detectable in our as grown samples. This levels concentration follows the increasing N-implantation density. The depth profiles of its concentration correlate with the distribution of implantation defects expected from Monte-Carlo simulation. After annealing at 900°C for 60s the additional defect level vanishes. The DLTS spectrum then resembles those of annealed as grown samples. The n-type carrier concentration (CV measurements) increases in samples with low N-implantation dose. This implantation effect can be removed also with the RTA step. The increasing carrier concentration provides evidence that the N vacancy is a donor in GaN. For Zn and S doped GaN deep defect levels has been found, which are reported here.

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Formation of Intrinsic Defects at MBE-Grown GaAs/AlAs Interfaces

MRS Proceedings ◽

10.1557/proc-312-89 ◽

1993 ◽

Vol 312 ◽

Author(s):

P. Krispin ◽

R. Hey ◽

H. Kostial ◽

M. Höricke

Keyword(s):

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Depth Profiling ◽

Intrinsic Defects ◽

Capacitance Voltage ◽

Charge States ◽

Transient Spectroscopy ◽

Silicon Doped ◽

Arsenic Vacancy

AbstractWe report on a detailed investigation of MBE-grown isotype silicon-doped heterostructures by capacitance/voltage (C/V) technique and deep-level transient spectroscopy (DLTS). A sequence of electrically active defects is found. By depth profiling of the density of the dominant levels it is demonstrated that the corresponding defects are concentrated at the GaAs-on-AlAs (inverted) interface. By comparison with studies on irradiation-induced levels in LPE- or VPE-grown AlGaAs we conclude that the defects at the GaAs/AlAs interface are most probably linked to different charge states of the arsenic vacancy VAs and VAs−ASi pairs.

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Impact of Low Temperature Hydrogenation on Recombination Activity of Dislocations in Silicon

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.108-109.151 ◽

2005 ◽

Vol 108-109 ◽

pp. 151-156

Author(s):

O.F. Vyvenko ◽

Martin Kittler ◽

Winfried Seifert

Keyword(s):

Low Temperature ◽

Deep Level ◽

Tight Binding ◽

Beam Current ◽

Electron Beam Current ◽

Recombination Activity ◽

Electrical Field ◽

Dissolved Iron ◽

Capacitance Voltage ◽

Transient Spectroscopy

Silicon samples doped with gallium and intentionally contaminated with iron have been studied by means of electron beam current (EBIC), capacitance voltage (CV) and deep level transient spectroscopy (DLTS) methods. Reverse bias anneal (RBA) treatments at temperatures of 390-420K were used to move hydrogen and dissolved iron atoms away from the surface. A new procedure was developed to find dislocations lying on desirable depth from the surface and to analyze the depth distribution of their recombination contrast. Iron contaminated dislocations do not noticeably change their recombination activity when kept in an electrical field as high as 104 V/cm at 420K for several hours. This implies a tight binding of iron atoms at dislocations. The binding energy of iron with dislocations seems to be much larger than for Fe-Ga and H-Ga pairs. Low temperature hydrogenation of iron contaminated dislocations does not produce any passivation effect. In opposite, the recombination activity of the dislocations significantly increases after RBA treatment.

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