Effect Of High Concentration Of Defect States At PS/c-Si Heterointerface On Transport Properties Of Al/PS/c-Si Photodiode Structures

1997 ◽  
Vol 486 ◽  
Author(s):  
L. A. Balagurov ◽  
A. F. Orlov ◽  
E. A. Petrova ◽  
D. G. Yarkin ◽  
S. Ya. Andryushin
Keyword(s):  
Porous Silicon ◽  
Open Circuit ◽  
High Resistivity ◽  
Defect States ◽  
High Concentration ◽  
Band Bending ◽  
Current Voltage ◽  
Electron Beam Induced Current ◽  
Charged Defects ◽  
Two Sides

AbstractCurrent-voltage characteristics, photosensitivity, frequency dependence of impedance, and electron beam induced current were measured for Al/porous silicon/c-Si structures with porous silicon (PS) layers of 60 and 80% porosity. Al/PS/c-Si structures have photosensitivity spectra typical for Al/c-Si structures. The sign of open circuit voltage changes in these structures when the wavelength becomes less than approximately 0.4 μm. It was shown that photosensitivity of Al/PS/c-Si structures and impedance dependence on the frequency, reverse bias and thickness of PS layer are completely determined by the PS layer of high resistivity and by the space charge region in c-Si substrate on PS/c-Si heterojunction. The annealing at above 100° C leads to a decrease of the forward current at a small bias. The photosensitivity of annealed structures reaches 10 A/W for some of the structures. The experimental results lead to inevitable conclusion about opposite band bending from the two sides of the heterojunction which is caused by high concentration of charged defects at PS/c-Si heterointerface. PS photodetectors with improved device parameter were obtained.

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

Metal/Porous Silicon Schottky Diode Structures as Sensors

2006 ◽  
Vol 915 ◽  
Author(s):  
Tayyar Dzhafarov ◽  
Cigdem Oruc Lus ◽  
Sureyya AYDIN ◽  
Emel Cingi
Keyword(s):  
Porous Silicon ◽  
Schottky Diode ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Current Voltage ◽  
Schottky Type ◽  
Capacitance Characteristics

AbstractIn this work we present data on investigation of the current-voltage and capacitance characteristics of Au/PS Schottky type structures in the presence of different hydrogen-containing solutions (glucose, ethanol, methanol, boric acid, sodium tetraborate pentahydrate, sodium borohydride, benzine, KOH). Generation of the open-circuit voltage and short-circuit current density and capacitance up to 0.55 V, 25 mA/cm2 and 1μF respectively on placing of Au/PS structures in these solutions was discovered. This effect is mainly caused by hydrogen component of solutions. The possible mechanism generation of voltage and capacitance in metal/PS sensors hydrogen-containing solutions is suggested. The advantage of metal/PS Schottky type sensors consists in working without applying external electricity.

scholarly journals Electrophysical Properties of GaAs P–I–N Structures for Concentrator Solar Cell Applications

2016 ◽  
Vol 67 (5) ◽  
pp. 377-382 ◽  
Author(s):  
Arpád Kósa ◽  
Miroslav Mikolášek ◽  
Ľubica Stuchlíková ◽  
Ladislav Harmatha ◽  
Wojciech Dawidowski ◽  
...  
Keyword(s):  
Solar Cell ◽  
Dark Current ◽  
Open Circuit Voltage ◽  
Deep Level ◽  
Open Circuit ◽  
Electrophysical Properties ◽  
Fourier Spectroscopy ◽  
Defect States ◽  
Current Voltage ◽  
Sun Light

AbstractThis paper is dedicated to electro-physical characterisation of a GaAs p-i-n structure grown for solar cell applications, which was carried out by light and dark current-voltage (I–V) and Deep Level Transient Fourier Spectroscopy (DLTFS) methods. The conversion efficiency and open-circuit voltage were determined fromI–Vmeasurement at 1 and 20× sun light concentrations. Three electron like defects TAn1, TAn2, TDnand one hole like defect TBp obtained by DLTFS measurements were confirmed. The origin of these defect states was stated as native GaAs impurities.

Laser Engineering of Barrier Structures Based on Solid Solution ZnCdHgTe.

2002 ◽  
Vol 719 ◽  
Author(s):  
Galina Khlyap
Keyword(s):  
Room Temperature ◽  
Film Surface ◽  
Charge Carriers ◽  
Barrier Structure ◽  
Free Charge ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Laser Engineering ◽  
Charged Defects ◽  
Epilayer Surface

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.

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.

On the Role of Charged Defect States and Deep Traps in the Photocarrier Drift and Diffusion in a-Si:H

2000 ◽  
Vol 609 ◽  
Author(s):  
Paul Stradins ◽  
Akihisa Matsuda
Keyword(s):  
Particle Number ◽  
Defect States ◽  
Total Electron ◽  
Minority Carrier Diffusion Length ◽  
Continuity Equations ◽  
Effective Mobility ◽  
Almost All ◽  
Charged Defects ◽  
And Diffusion

ABSTRACTThe drift and diffusion in the presence of charged defects and photocarriers trapped in the tail states is re-examined. In continuity equations, diffusive and drift currents are related to free particles while the Poisson equation includes all charges. In order to make use of ambipolar diffusion approximation, the mobilities and diffusion coefficients should be attributed to the total electron and hole populations making them strongly particle-number dependent. Due to the asymmetry of the conduction and valence band tails, almost all trapped electrons reside in negatively charged defects (D−). A simple model of photocarrier traffic via tail and defect states allows to establish the effective mobility values and coefficients in Einstein relations. In a photocarrier grating experiment, grating of D− is counterbalanced by the grating of trapped holes. Nevertheless, electrons remain majority carriers, allowing the measurement of minority carrier diffusion length, but analysis is needed to relate the latter with μτ product.

Electrical Measurement of Recombination Lifetime in Blue Light Emitting Diodes

2004 ◽  
Vol 829 ◽  
Author(s):  
M. A. Awaah ◽  
R. Nana ◽  
K. Das
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Deep Level ◽  
Electrical Measurement ◽  
High Concentration ◽  
Recombination Lifetime ◽  
Light Emitting ◽  
Radiative Processes ◽  
Current Voltage ◽  
Capacitance Voltage

ABSTRACTA recombination lifetime of approximately 25 ns was extracted from measured reverse recovery storage times in AlGaN/GaN/AlGaN double heterojunction blue light emitting diodes. This experimentally determined lifetime is expected to arise from a combination of radiative and non-radiative processes occurring in the diodes. The non-radiative processes are likely to be due the presence of a high concentration deep-states as identified from the current-voltage and capacitance-voltage measurements. Current-voltage characteristics of these diodes were highly non-ideal as indicated by high values of the ideality factor ranging from 3.0 – 7.0. Logarithmic plots of the forward characteristics indicated a space-charge-limited-current (SCLC) conduction in presence of a high density of “deep-level states” in the active region of the diodes. An analysis of these characteristics yielded an approximate density of these deep-level states as 2 × 1017/cm3. The density of deep-states extracted from capacitance-voltage measurements were in good agreement with that obtained from current-voltage measurements.

scholarly journals Simulation of a perovskite sandwich solar cell with the p-CZTS / p-CH3NH3PbCI3 / p-CZTS absorber layers

2021 ◽  
Vol 877 (1) ◽  
pp. 012001
Author(s):  
Marwah S Mahmood ◽  
N K Hassan
Keyword(s):  
Solar Cell ◽  
Conversion Efficiency ◽  
Current Density ◽  
Short Circuit ◽  
Perovskite Solar Cells ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Current Voltage ◽  
Cell Capacitance

Abstract Perovskite solar cells attract the attention because of their unique properties in photovoltaic cells. Numerical simulation to the structure of Perovskite on p-CZTS/p-CH3NH3PbCI3/p-CZTS absorber layers is performed by using a program solar cell capacitance simulator (SCAPS-1D), with changing absorber layer thickness. The effect of thickness p-CZTS/p-CH3NH3PbCI3/p-CZTS, layers at (3.2μm, 1.8 μm, 1.1 μm) respectively are studied. The obtained results are short circuit current density (Jsc ), open circuit voltage (V oc), fill factor (F. F) and power conversion efficiency (PCE) equal to (28 mA/cm2, 0.83 v, 60.58 % and 14.25 %) respectively at 1.1 μm thickness. Our findings revealed that the dependence of current - voltage characteristics on the thickness of the absorbing layers, an increase in the amount of short circuit current density with an increase in the thickness of the absorption layers and thus led to an increase in the conversion efficiency and improvement of the cell by increasing the thickness of the absorption layers.

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