3D Distributions of Chlorine and Sulphur Impurities in a Thin-Film Cadmium Telluride Solar Cell

MRS Advances ◽  
2018 ◽  
Vol 3 (56) ◽  
pp. 3287-3292 ◽  
Author(s):  
Thomas A. M. Fiducia ◽  
Kexue Li ◽  
Amit H. Munshi ◽  
Kurt Barth ◽  
Walajabad S. Sampath ◽  
...  
Keyword(s):  
Cadmium Telluride ◽  
Cadmium Chloride ◽  
High Efficiency ◽  
Cadmium Sulphide ◽  
Diffusion Profile ◽  
Lattice Diffusion ◽  
Three Dimensions ◽  
Device Performance ◽  
Extended Defects ◽  
Cdte Solar Cells

ABSTRACTA cadmium chloride activation treatment is essential for the production of high efficiency cadmium telluride (CdTe) solar cells. However, the effects of the treatment on the distributions of chlorine and sulphur within the device are not fully understood. Here, the detailed locations of chlorine and sulphur in a treated CdTe cell are determined in three dimensions by high resolution dynamic SIMS measurements. Chlorine is found to be present in grain boundaries, grain interiors, extended defects within the grain interiors, at the front interface, and in the cadmium sulphide layer. In each of these regions, the chlorine is likely to have significant effects on local electronic properties of the material, and hence overall device performance. Sulphur is found to have a U-shaped diffusion profile within CdTe grains, indicating a mixed grain boundary and lattice diffusion regime.

The Effect of Annealing Treatments on Close Spaced Sublimated Cadmium Telluride Thin Film Solar Cells

2013 ◽  
Vol 1493 ◽  
pp. 147-152 ◽  
Author(s):  
J.M. Walls ◽  
A. Abbas ◽  
G. D. West ◽  
J.W. Bowers ◽  
P.J.M. Isherwood ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Cadmium Telluride ◽  
Cadmium Chloride ◽  
High Efficiency ◽  
Stacking Faults ◽  
Annealing Treatment ◽  
Complete Removal ◽  
Close Space Sublimation ◽  
Transmission Electron

ABSTRACTIt is well known that the cadmium chloride annealing treatment is an essential step in the manufacture of efficient thin film cadmium telluride solar cells. It has been recognized that the combination of annealing at ∼4000C together with the addition of cadmium chloride at the surface induces re-crystallisation of the cadmium telluride layer and also affects the n-type cadmium sulfide. We have applied advanced micro-structural characterization techniques to distinguish the effect of the annealing and the cadmium chloride treatments on the properties of the cadmium telluride deposited via close space sublimation (CSS) and relate these observations to device performance. Transmission electron microscopy (TEM) has shown a variation in stacking fault density with annealing temperature and annealing time. Stacking faults observed within the cadmium telluride grains in TEM were partially removed post annealing; these findings show that temperature alone has a role in the reduction of stacking faults. However, since we have previously observed almost complete removal of stacking faults with annealing in combination with cadmium chloride, the cadmium chloride is essential to defect removal and high efficiency cells.

Cadmium Chloride Assisted Re-Crystallization of CdTe: The Effect of Varying the Annealing Time

2014 ◽  
Vol 1638 ◽  
Author(s):  
A. Abbas ◽  
G. D. West ◽  
J.W. Bowers ◽  
P. M. Kaminski ◽  
B. Maniscalco ◽  
...  
Keyword(s):  
Cadmium Telluride ◽  
Cadmium Chloride ◽  
High Efficiency ◽  
Morphological Changes ◽  
Depth Profiling ◽  
Annealing Treatment ◽  
Photovoltaic Devices ◽  
Micro Structure ◽  
Transmission Electron ◽  
Chloride Treatment

ABSTRACTAlthough the cadmium chloride treatment is an essential process for high efficiency thin film cadmium telluride photovoltaic devices, the precise mechanisms involved that improve the cadmium telluride layer are not well understood. In this investigation we apply advanced micro-structural characterization techniques to study the effect of varying the time of the cadmium chloride annealing treatment on the micro-structure of cadmium telluride solar cells deposited by close spaced sublimation (CSS) and relate this to cell performance. A range of techniques has been used to observe the morphological changes to the micro-structure as well as the chemical and crystallographic changes as a function of treatment parameters. Electrical tests that link the device performance with the micro-structural properties of the cells have also been undertaken. Techniques used include Transmission Electron Microscopy (TEM) for sub-grain analysis and XPS for composition-depth profiling. The study provides a new insight in to the mechanisms involved in the initiation and the subsequent complete re-crystallization of the cadmium telluride layer.

scholarly journals Tailoring the Geometry of Bottom-Up Nanowires: Application to High Efficiency Single Photon Sources

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1201
Author(s):  
Dan Dalacu ◽  
Philip J. Poole ◽  
Robin L. Williams
Keyword(s):  
Quantum Dot ◽  
High Efficiency ◽  
Emission Rate ◽  
Single Photon ◽  
Collection Efficiency ◽  
Photon Emission ◽  
Device Performance ◽  
Bottom Up ◽  
Selective Area ◽  
Photon Generation

For nanowire-based sources of non-classical light, the rate at which photons are generated and the ability to efficiently collect them are determined by the nanowire geometry. Using selective-area vapour-liquid-solid epitaxy, we show how it is possible to control the nanowire geometry and tailor it to optimise device performance. High efficiency single photon generation with negligible multi-photon emission is demonstrated using a quantum dot embedded in a nanowire having a geometry tailored to optimise both collection efficiency and emission rate.

Stable, high efficiency thin film solar cells produced by electrodeposition of cadmium telluride

1991 ◽  
Vol 23 (2-4) ◽  
pp. 388-393 ◽  
Author(s):  
A.K. Turner ◽  
J.M. Woodcock ◽  
M.E. Ozsan ◽  
J.G. Summers ◽  
J. Barker ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Cadmium Telluride ◽  
High Efficiency ◽  
Thin Film Solar Cells

COMPARATIVE ANALYSIS OF RECENT HIGH-EFFICIENCY CdTe SOLAR CELLS

1992 ◽  
Vol 12 (1-4) ◽  
pp. 17-24 ◽  
Author(s):  
R. A. SASALA ◽  
X. X. LIU ◽  
J. R. SITES
Keyword(s):  
Solar Cells ◽  
Comparative Analysis ◽  
High Efficiency ◽  
Cdte Solar Cells

Inversion of slingram electromagnetic induction data using a Born approximation

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. E201-E212 ◽  
Author(s):  
Jochen Kamm ◽  
Michael Becken ◽  
Laust B. Pedersen
Keyword(s):  
Half Space ◽  
Born Approximation ◽  
High Efficiency ◽  
Three Dimensions ◽  
Background Model ◽  
Desktop Computer ◽  
Near Surface ◽  
Homogeneous Half Space ◽  
Integral Equation Formulation ◽  
Forward Operator

We present an efficient approximate inversion scheme for near-surface loop-loop EM induction data (slingram) that can be applied to obtain 2D or 3D models on a normal desktop computer. Our approach is derived from a volume integral equation formulation with an arbitrarily conductive homogeneous half-space as a background model. The measurements are not required to fulfill the low induction number condition (low frequency and conductivity). The high efficiency of the method is achieved by invoking the Born approximation around a half-space background. The Born approximation renders the forward operator linear. The choice of a homogeneous half-space yields closed form expressions for the required electromagnetic normal fields. It also yields a translationally invariant forward operator, i.e., a highly redundant Jacobian. In connection with the application of a matrix-free conjugate gradient method, this allows for very low memory requirements during the inversion, even in three dimensions. As a consequence of the Born approximation, strong conductive deviations from the background model are underestimated. Highly resistive anomalies are in principle overestimated, but at the same time difficult to resolve with induction methods. In the case of extreme contrasts, our forward model may fail in simultaneously explaining all the data collected. We applied the method to EM34 data from a profile that has been extensively studied with other electromagnetic methods and compare the results. Then, we invert three conductivity maps from the same area in a 3D inversion.

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