Non-Local Recombination in “Tunnel Junctions” of Multijunction Amorphous Si Alloy Solar Cells

1994 ◽  
Vol 336 ◽  
Author(s):  
Jingya Hou ◽  
Jianping Xi ◽  
Frank Kampas ◽  
Sanghoon Bae ◽  
S. J. Fonash
Keyword(s):  
Solar Cells ◽  
Tunnel Junction ◽  
Tunnel Junctions ◽  
Energy Conversion Efficiency ◽  
State Density ◽  
Defect State ◽  
Large Defect ◽  
Recombination Mechanism ◽  
Non Local ◽  
Amorphous Si

ABSTRACTThis paper analyzes the charge transport in “tunnel junctions” of amorphous Si Material based multijunction solar cells and proposes some guidelines for making good “tunnel junctions” based on the analysis. The Mechanism of the current flow in these “tunnel” junctions is recombination. However, the recombination mechanism is not the usual localized recombination but is non-localized recombination. The energy analysis shows that the usual localized recombination will cause a large energy loss and result in much lower energy conversion efficiency and Voc than the experimentally measured values. In non-local recombination, opposite charge carriers located at different locations can recombine by tunneling into a defect state. Based on this Mechanism, a good “tunnel junction” should be thin, with a large defect state density in the middle region of the “tunnel junction”. Broad tail states material and a thin layer small band gap material in tunnel junctions may improve the non-local recombination by providing more intermediate states for charge to tunnel through.

The Study of Deep Levels in CdS/CdTe Solar Cells Using Admittance Spectroscopy and its Modifications

2003 ◽  
Vol 763 ◽  
Author(s):  
A.S. Gilmore ◽  
V. Kaydanov ◽  
T.R. Ohno
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Wide Frequency Range ◽  
State Density ◽  
Defect State ◽  
Stress Tests ◽  
Frequency Range ◽  
Cdte Solar Cells ◽  
State Densities ◽  
As Stress

AbstractMeasurements of an admittance over a wide frequency range were used to detect the defect electronic states and evaluate their properties in CdTe based solar cells. Cells prepared in various ways, from various facilities all exhibited a high defect state density (>1014cm-3, and often >1015cm-3). Two distinct energy levels or bands were observed at approximately 0.37eV and 0.61eV above the valence band. These were tentatively attributed to CuCd- and VCd-- respectively. Various post-CdTe deposition treatments, as well as stress tests, were applied to alter the defect state densities. The high defect concentration measured was not observed to inhibit cell performance in any way.

Microcrystalline Silicon Tunnel Junctions for Amorphous Silicon-Based Multijunction Solar Cells

1999 ◽  
Vol 557 ◽  
Author(s):  
A. S. Ferlauto ◽  
Joohyun Koh ◽  
P. I. Rovira ◽  
C. R. Wronski ◽  
R. W. Collins
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Tunnel Junction ◽  
Single Phase ◽  
Film Growth ◽  
Tunnel Junctions ◽  
Microcrystalline Silicon ◽  
Evolutionary Phase ◽  
Two Phases ◽  
P Type

AbstractThe formation of tunnel junctions for applications in amorphous silicon (a-Si:H) based multijunction n-i-p solar cells has been studied using real time optics. The junction structure investigated in detail here consists of a thin (~200 Å) layer of n-type microcrystalline silicon (μc-Si:H) on top of an equally thin layer of p-type μc-Si:H, the latter deposited on thick (~2000 Å) intrinsic a-Si:H. Such a structure has been optimized in an attempt to obtain single-phase μc-Si:H with a high crystallite packing density and large grain size for both layers of the tunnel junction. We have explored the conditions under which grain growth is continuous across the p/n junction and conditions under which renucleation of n-layer grains can be ensured at the junction. One important finding of this study is that the optimum conditions for single-phase, high-density μc-Si:H n-layers are different depending on whether the substrate is a μc-Si:H p-layer or is a H2-plasma treated or untreated a-Si:H i-layer. Thus, the top-most μc-Si:H layer of the tunnel junction must be optimized in the multijunction device configuration, rather than in single cell configurations on a-Si:H i-layers. Our observations are explained using an evolutionary phase diagram for a-Si:H and μc-Si:H film growth versus thickness and H2-dilution ratio, in which the boundary between the two phases is strongly substrate-dependent.

scholarly journals Tunnel Junctions for III-V Multijunction Solar Cells Review

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 445 ◽  
Author(s):  
Peter Colter ◽  
Brandon Hagar ◽  
Salah Bedair
Keyword(s):  
Solar Cells ◽  
Tunnel Junction ◽  
Tunnel Junctions ◽  
Current Standard ◽  
Space Applications ◽  
Doped Semiconductors ◽  
Significant Performance ◽  
And Performance ◽  
Transparent Semiconductor ◽  
Performance Gains

Tunnel Junctions, as addressed in this review, are conductive, optically transparent semiconductor layers used to join different semiconductor materials in order to increase overall device efficiency. The first monolithic multi-junction solar cell was grown in 1980 at NCSU and utilized an AlGaAs/AlGaAs tunnel junction. In the last 4 decades both the development and analysis of tunnel junction structures and their application to multi-junction solar cells has resulted in significant performance gains. In this review we will first make note of significant studies of III-V tunnel junction materials and performance, then discuss their incorporation into cells and modeling of their characteristics. A Recent study implicating thermally activated compensation of highly doped semiconductors by native defects rather than dopant diffusion in tunnel junction thermal degradation will be discussed. AlGaAs/InGaP tunnel junctions, showing both high current capability and high transparency (high bandgap), are the current standard for space applications. Of significant note is a variant of this structure containing a quantum well interface showing the best performance to date. This has been studied by several groups and will be discussed at length in order to show a path to future improvements.

First-principles study on the electronic and optical properties of the orthorhombic CsPbBr3 and CsPbI3 with Cmcm space group

2021 ◽  
Author(s):  
Xianhao Zhao ◽  
Tianyu Tang ◽  
Quan Xie ◽  
like gao ◽  
Limin Lu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
First Principles ◽  
Energy Conversion Efficiency ◽  
Space Group ◽  
Absorbing Materials ◽  
Halide Perovskites ◽  
Lead Halide

The cesium lead halide perovskites are regarded as effective candidates for light-absorbing materials in solar cells, which have shown excellent performances in experiments such as promising energy conversion efficiency. In...

TiO2 cement for high-performance dye-sensitized solar cells

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 83802-83807 ◽  
Author(s):  
Yu Hou ◽  
Shuang Yang ◽  
Chunzhong Li ◽  
Huijun Zhao ◽  
Hua Gui Yang
Keyword(s):  
Solar Cells ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
High Performance ◽  
Dye Sensitized Solar Cells ◽  
Energy Conversion Efficiency ◽  
Dye Sensitized ◽  
Degussa P25 ◽  
Sensitized Solar Cells

An energy conversion efficiency of 8.31% is reached by using a cemented photoanode for dye-sensitized solar cells, attaining a 31.1% improvement over the standard Degussa P25 sample.

Modeling of tunnel junctions for high efficiency solar cells

2010 ◽  
Vol 97 (4) ◽  
pp. 042111 ◽  
Author(s):  
John R. Hauser ◽  
Zach Carlin ◽  
S. M. Bedair
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Tunnel Junctions ◽  
High Efficiency Solar Cells
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