Radiative mechanism and surface modification of four visible deep level defect states in ZnO nanorods

Nanoscale ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 995-1006 ◽  
Author(s):  
E. G. Barbagiovanni ◽  
R. Reitano ◽  
G. Franzò ◽  
V. Strano ◽  
A. Terrasi ◽  
...  
Keyword(s):  
Surface Modification ◽  
Deep Level ◽  
Zno Nanorods ◽  
Defect States ◽  
Deep Level Defect ◽  
Radiative Mechanism

scholarly journals Improved Ultraviolet Photoresponse Properties of ZnO Nanorods Grown by Using Hydrothermal Method Applied Rotating Precursor Solution

2021 ◽  
Vol 59 (3) ◽  
pp. 187-194
Author(s):  
Dongwan Kim ◽  
Jae-Young Leem
Keyword(s):  
Surface Modification ◽  
Hydrothermal Method ◽  
Rotation Rate ◽  
Deep Level ◽  
Zno Nanorods ◽  
Precursor Solution ◽  
Near Band Edge ◽  
High Reproducibility ◽  
Axis Orientation ◽  
Diffraction Peaks

We grew ZnO nanorods (NRs) using a hydrothermal method while rotating the precursor solution, and report the effect of rotation on surface modification, and the optical and ultraviolet (UV) photoresponse properties of the resulting ZnO nanorods. The ZnO NRs grown in the rotating precursor solution at 100 rpm had the longest length and diameter, which decreased with increasing rotation rate above 100 rpm. Also, the intensity of the diffraction peaks from ZnO (002) and (100) was strongest and weakest for the ZnO NRs grown in a rotating solution at 150 rpm, respectively, indicating improvement in the c-axis orientation of the ZnO NRs. In the PL spectra, near-band-edge (NBE) and deep-level (DL) emissions were observed from all of the ZnO NRs. The intensity of the NBE emission gradually increased with increasing rotation rate, due to the increase in surface area. Also, the intensity of the DL emission gradually increased with increasing rotation rate because of the increasing number of interstitial oxygens. Analysis of the UV photoresponse found the photocurrent of the ZnO NRs grown in the rotating precursor solution was higher than that of ZnO NRs grown in a non-rotated precursor solution. In particular, ZnO NRs grown in a rotating precursor solution at 150 rpm exhibited the highest value of photosensitivity, with high reproducibility.

Improvement In Electrical Properties of Polycrystalline Silicon Films by The H2O Vapor Annealing Method

2001 ◽  
Vol 664 ◽  
Author(s):  
Toshiyuki Sameshima ◽  
Katsimi Asada ◽  
Yoshiyuki Tsunoda ◽  
Yoshiyasu Kaneko
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Electrical Properties ◽  
High Performance ◽  
Deep Level ◽  
Silicon Films ◽  
Defect States ◽  
Deep Level Defect ◽  
Vapor Annealing ◽  
Polycrystalline Silicon Films

ABSTRACTImprovement of electrical properties by heat treatment with high-pressure H2O vapor was discussed for 7.4×1017cm−3 phosphorus-doped pulsed laser crystallized silicon films. The analysis of the electrical conductivity resulted in that 1.3×106-Pa-H2O vapor annealing at 270°C for 3 h reduced the density of defect states from 5.5 ×1018 cm−3(as crystallized) to 5.0×1017 cm−3 for tail states and from 1.0×1018 cm−3(as crystallized) to 3.0×1017 cm−3 for deep level defect states. The potential barrier height at grain boundaries decreased from 0.34 eV (as crystallized) to 0.05 eV by the heat treatment. The combination of oxygen plasma with high-pressure H2O vapor annealing effectively reduced the densities of defect tail sates as well as deep level defect states. It achieved a high performance of thin film transistors with a threshold voltage of 1.3 V and an effective mobility of 160 cm2/Vs.

Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen

2003 ◽  
Vol 766 ◽  
Author(s):  
V. Ligatchev ◽  
T.K.S. Wong ◽  
T.K. Goh ◽  
Rusli Suzhu Yu
Keyword(s):  
Deep Level ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Reverse Bias Voltage ◽  
Defect States ◽  
Single Side ◽  
Sandwich Type ◽  
Transient Spectroscopy ◽  
P Type ◽  
Spectrum Deconvolution

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.

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

Materials ◽  
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.

The Peculiarities of Deep Level Defect Passivation in SI by Atomic Hydrogen

1989 ◽  
Vol 6-7 ◽  
pp. 341-342
Author(s):  
Sergei V. Koveshnikov ◽  
S.V. Nosenko ◽  
Eugene B. Yakimov
Keyword(s):  
Atomic Hydrogen ◽  
Deep Level ◽  
Deep Level Defect ◽  
Defect Passivation

Study of Deep Level Defect in Polycrystalline Cadmium Sulfide Films

1998 ◽  
pp. 255-261
Author(s):  
U. Pal ◽  
R. Silva González ◽  
F. Donado ◽  
M. L. Hernández ◽  
J. M. Gracia-Jiménez
Keyword(s):  
Cadmium Sulfide ◽  
Deep Level ◽  
Deep Level Defect

Characterization of traps in InAlN by optically and thermally stimulated deep level defect spectroscopies

2018 ◽  
Vol 124 (14) ◽  
pp. 145703 ◽  
Author(s):  
Esmat Farzana ◽  
Humberto M. Foronda ◽  
Christine M. Jackson ◽  
Towhidur Razzak ◽  
Zeng Zhang ◽  
...  
Keyword(s):  
Deep Level ◽  
Deep Level Defect

Defect Spectroscopy on Damp-Heat Treated ZnO/CdS/Cu(In,Ga)(S,Se)2/Mo Heterojunction Solar Cells

2003 ◽  
Vol 58 (12) ◽  
pp. 691-702 ◽  
Author(s):  
C. Deibel ◽  
V. Dyakonov ◽  
J. Parisi
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Solar Cells ◽  
Deep Level ◽  
Heat Exposure ◽  
Continuous Distribution ◽  
Open Circuit ◽  
Defect States ◽  
Band Bending ◽  
Test Cells

The changes of defect characteristics induced by accelerated lifetime tests on solar cells of the heterostructure ZnO/CdS/Cu(In,Ga)(S,Se)2/Mo are investigated. Encapsulated modules were shown to be stable against water vapor and oxygen under outdoor conditions, whereas the fill factor and open-circuit voltage of non-encapsulated test cells are reduced after prolonged damp heat treatment in the laboratory, leading to a reduced energy conversion efficiency. We subjected non-encapsulated test cells to extended damp heat exposure at 85 ◦C ambient temperature and 85% relative humidity for various time periods (6 h, 24 h, 144 h, 294 h, and 438 h). In order to understand the origin of the pronounced changes of the cells, we applied temperature-dependent current-voltage and capacitance voltage measurements, admittance spectroscopy, and deep-level transient spectroscopy. We observed the presence of electronic defect states which show an increasing activation energy due to damp heat exposure. The corresponding attempt-to-escape frequency and activation energy of these defect states obey the Meyer-Neldel relation. We conclude that the response originates from an energetically continuous distribution of defect states in the vicinity of the CdS/chalcopyrite interface. The increase in activation energy indicates a reduced band bending at the Cu(In,Ga)(S,Se)2 surface.We also observed changes in the bulk defect spectra due to the damp-heat treatment. - PACS: 73.20.hb, 73.61.Le

Insights on the impact of photophysical processes and defect states evolution on the emission properties of surface-modified ZnO nanoplates for application in photocatalysis and hybrid LEDs

2021 ◽  
Author(s):  
Dhritiman Banerjee ◽  
Payal Banerjee ◽  
Asit Kumar Kar
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Surface Modification ◽  
Defect State ◽  
Defect States ◽  
Emission Properties ◽  
Photophysical Processes ◽  
State Densities ◽  
Surface Modified ◽  
The Impact

The effects of surface modification on the defect state densities, optical properties, photocatalytic and quantum efficiencies of zinc oxide (ZnO) nanoplates have been studied in this work. Here, the aim...

Capacitance and Current Deep-Level Transient Fourier Spectroscopy (DLTFS) for the Characterization of Defect States in Mg-Doped GaN-on-Si p+n Diodes

2021 ◽  
Vol MA2021-01 (34) ◽  
pp. 2043-2043
Author(s):  
Yoann Lechaux ◽  
Albert Minj ◽  
Laurence Méchin ◽  
Hu Liang ◽  
Karen Geens ◽  
...  
Keyword(s):  
Deep Level ◽  
Fourier Spectroscopy ◽  
Defect States ◽  
Gan On Si ◽  
Mg Doped
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