Structural Evolution of Top-Junction a-Si:C:H:B and Mixed-Phase (Microcrystalline Si)-(a-Sil-xCx:H) p-Layers in a-Si:H n-i-p Solar Cells

1996 ◽  
Vol 420 ◽  
Author(s):  
Joohyun Koh ◽  
J. S. Burnham ◽  
Yeeheng Li ◽  
Hongyue Liu ◽  
Ing-Shin Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Volume Fraction ◽  
Structural Evolution ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Mixed Phase ◽  
Continuous Film ◽  
Layer Deposition ◽  
The Individual ◽  
Hydrogenated Amorphous

AbstractWe have applied real time spectroellipsometry (RTSE) to study hydrogenated amorphous silicon (a-Si:H) solar cells fabricated in the Cr/n-i-p configuration using plasma-enhanced chemical vapor deposition (PECVD) in a single-chamber system. The microstructural evolution of the n-, i-, and p-layers of the devices has been determined, including the thicknesses of the bulk, interface, and surface roughness layers versus time. The optical properties of the individual layers, including the dielectric functions and optical gaps, have also been obtained in the same analysis. In this study, we have focused on i/p interface formation and, in particular, on the nucleation process for differently-prepared a-Si:C:H and mixed-phase μc-Si:H/a-Si1-xCx:H p-layers on the a-Si:H i-layer. From the thickness dependence of the p-layer void volume fraction, we can obtain an estimate of the thickness at which nuclei make contact to form a continuous film. For the mixed-phase p-layers, the nuclei contact thickness can be reduced by exposing the i-layer to a H2-plasma prior to p-layer deposition. We have found that for similarly-prepared p-layers this reduction in contact thickness leads to an increase in open-circuit voltage of the solar cell

Efficient 18 Å/s Solar Cells with All Silicon Layers Deposited by Hot-Wire Chemical Vapor Deposition

2000 ◽  
Vol 609 ◽  
Author(s):  
Qi Wang ◽  
Eugene Iwaniczko ◽  
Yueqin Xu ◽  
Wei Gao ◽  
Brent P. Nelson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Hot Wire ◽  
Edge Layer ◽  
Hydrogenated Amorphous ◽  
Sun Light

ABSTRACTEfficient hydrogenated amorphous silicon (a-Si:H) n-i-p solar cells have been fabricated with all doped and undoped a-Si:H layers deposited by hot-wire chemical vapor deposition (HWCVD). The total deposition time of all layers, except the top ITO-contact, is less than 4 minutes. On an untextured stainless steel (SS) substrate, an initial efficiency of 7.12% is reached, with a stable efficiency of 5.4% after 1000 hours 1 sun light soaking. This initial efficiency is reached by incorporating into the p/i interface about 60 Å of intrinsic a-Si:H “edge” material grown under conditions near the transition to microcrystallinity. This edge layer increases the cell's fill factor from 0.60 to 0.68 and the best open-circuit voltage is about 0.88 V. Using textured Ag/ZnOcoated SS supplied by United Solar Corporation, preliminary results of an all-HWCVD solar cell give an initial efficiency of 8.7 %.

Local Current Flow in Mixed-Phase Silicon Solar Cells and Correlation to Light-Induced Open-Circuit Voltage Enhancement

2006 ◽  
Vol 910 ◽  
Author(s):  
Baojie Yan ◽  
C.-S. Jiang ◽  
H. R. Moutinho ◽  
M. M. Al-Jassim ◽  
Jeffrey Yang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Current Flow ◽  
Volume Fraction ◽  
Cell Structure ◽  
Open Circuit ◽  
Phase Region ◽  
Mixed Phase ◽  
High Current ◽  
Conductive Atomic Force Microscopy ◽  
Local Current

AbstractWe use conductive atomic force microscopy (C-AFM) to measure the local current flow in the mixed-phase hydrogenated silicon n-i-p solar cell structure without the top ITO contact. The forward biased C-AFM images reveal that for the fully amorphous region the current is very low on the entire surface. However, high current spikes appear in the mixed-phase region, where the current spikes are correlated to the formation of nanocrystallite aggregations with a diameter of ~500 nm. Furthermore, the density of the current spikes increases from the mixed-phase to the substantially nanocrystalline regions. The nanocrystallite aggregation supports our previously proposed parallel-connected two-diode model for Voc drops with crystalline volume fraction and light-induced Voc increase in the mixed-phase solar cells. Adding a 50-nm thick a-Si:H buffer layer between the p and i layers significantly reduces the magnitude of the high current spikes, even the top morphology appears unaffected. This result is also consistent with the previously proposed two-diode model for explaining the carrier transport in the mixed-phase solar cells.

Correlation of Light-induced Enhancement of Open-Circuit Voltage and Structural Change of Heterogeneous Silicon Solar Cells

2002 ◽  
Vol 715 ◽  
Author(s):  
Jeffrey Yang ◽  
Kenneth Lord ◽  
Baojie Yan ◽  
Arindam Banerjee ◽  
Subhendu Guha ◽  
...  
Keyword(s):  
Solar Cells ◽  
Structural Change ◽  
Open Circuit Voltage ◽  
Volume Fraction ◽  
Heterogeneous Material ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Energy Position ◽  
Layer Deposition ◽  
Peak Energy

AbstractWe observe a significant light-induced increase in the open-circuit voltage, Voc, of thin-film silicon solar cells whose intrinsic (i) layer consists of an amorphous and microcrystalline mixed phase. The increase depends on the i-layer thickness, the i-layer deposition temperature, the initial Voc values, and the light-soaking intensity. An increase of as large as 150 mV is observed. The original Voc is restored after subsequent thermal annealing. In-situ photoluminescence (PL) spectroscopy is used to investigate this metastable phenomenon. We find that the PL intensity and peak-energy position associated with the amorphous component of the heterogeneous material increase upon light soaking, suggesting a structural change. We propose that a reduction of microcrystalline volume fraction or size is responsible for the Voc enhancement.

P-layer Optimization in High Performance a-Si:H Solar Cells

2010 ◽  
Vol 1245 ◽  
Author(s):  
Yueqin Xu ◽  
Bill Nemeth ◽  
Falah Hasoon ◽  
Lusheng Hong ◽  
Anna Duda ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Fill Factor ◽  
Transparent Conducting Oxide ◽  
Critical Role ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Oxide Glass ◽  
Frequency Plasma ◽  
Hydrogenated Amorphous

AbstractWe report our progress toward high-performance hydrogenated amorphous silicon (a-Si:H) solar cells fabricated in NREL's newly installed multi-chamber film Si deposition system. The a-Si:H layers are made by standard radio frequency plasma-enhanced chemical vapor deposition. This system produces a-Si:H p-i-n single-junction devices on Asahi U-type transparent conducting oxide glass with >10% initial efficiency. The importance of the p-layer to the cell is identified: it plays a critical role in further improving cell performance. Our optimization process involves changing p-layer parameters such as dopant levels, bandgap, and thickness in cells as well as applying a double p-layer. With the optimized p-layer, we are able to increase the fill factor of our cells to as high as 72% while maintaining high open-circuit voltage.

Light-Induced Degradation in Solar Cells with Hydrogenated Amorphous Silicon-Sulfur Active Layers

2002 ◽  
Vol 715 ◽  
Author(s):  
Wei Xu ◽  
P. C. Taylor
Keyword(s):  
Solar Cells ◽  
Practical Importance ◽  
Chemical Vapor ◽  
Photovoltaic Devices ◽  
Sulfur Concentration ◽  
Active Layers ◽  
Conversion Efficiencies ◽  
Hydrogenated Amorphous ◽  
Secondary Ion ◽  
Initial Conversion

AbstractWe have made a series of a-SiSx:H based solar cells, with a pin structure, in a multichamber plasma enhanced chemical vapor deposition (PECVD) system. The sulfur concentration ranges from zero to 5 x 1018 cm-3 as measured by secondary ion mass spectroscopy. The initial conversion efficiencies of cells in this series with sulfur concentrations ≤ 1018 cm-3 are approximately 7%. The time constants for degradation increase with increasing sulfur concentration, but not fast enough to be of practical importance in photovoltaic devices.

Kinetics of Light-Induced Effects in Mixed-Phase Hydrogenated Silicon Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Guozhen Yuea ◽  
Baojie Yan ◽  
Jeffrey Yang ◽  
Kenneth Lord ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Equivalent Circuit Model ◽  
Open Circuit ◽  
Mixed Phase ◽  
Silicon Solar Cells ◽  
Initial Increase ◽  
Soaking Time ◽  
Hydrogenated Silicon ◽  
Kinetics Of

AbstractWe have observed a significant light-induced increase in the open-circuit voltage (Voc) of mixed-phase hydrogenated silicon solar cells. In this study, we investigate the kinetics of the light-induced effects. The results show that the cells with different initial Voc have different kinetic behavior. For the cells with a low initial Voc (less than 0.8 V), the increase in Voc is slow and does not saturate for light-soaking time of up to 16 hours. For the cells with medium initial Voc (0.8 ∼ 0.95 V), the Voc increases rapidly and then saturates. Cells with high initial Voc (0.95 ∼ 0.98 V) show an initial increase in Voc, followed bya Voc decrease. All light-soaked cells exhibit a degradation in fill factor. The temperature dependence of the kinetics shows that light soaking at high temperatures causes Voc increase to saturate faster than at low temperatures. The observed results can be explained by our recently proposed two-diode equivalent-circuit model for mixed-phase solar cells.

Effect of the Quantum Size Effect on the Performance of Solar Cells with a Silicon Nanowire Array Embedded in SiO2

2012 ◽  
Vol 1439 ◽  
pp. 145-150
Author(s):  
Yasuyoshi Kurokawa ◽  
Shinya Kato ◽  
Yuya Watanabe ◽  
Akira Yamada ◽  
Makoto Konagai ◽  
...  
Keyword(s):  
Solar Cells ◽  
Size Effect ◽  
Amorphous Silicon ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Hydrogenated Amorphous Silicon ◽  
Open Circuit ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Hydrogenated Amorphous

ABSTRACTThe electrical characteristics of silicon nanowire (SiNW) solar cells with p-type hydrogenated amorphous silicon oxide (Eg=1.9 eV)/n-type SiNWs embedded in SiO2/n-type hydrogenated amorphous silicon (Eg=1.7 eV) structure have been investigated using a two-dimensional device simulator with taking the quantum size effects into account. The average bandgap of a SiNW embedded in SiO2 increased from 1.15 eV to 2.71 eV with decreasing the diameter from 10 nm to 1 nm due to the quantum size effect. It should be noted that under the sunlight with AM1.5G the open-circuit voltage (Voc) of SiNW solar cells also increased to 1.54 V with decreasing the diameter of the SiNWs to 1 nm. This result suggests that it is possible to enhance the Voc by the quantum size effect and a SiNW is a promising material for the all silicon tandem solar cells.

scholarly journals Applications of atomic layer deposition and chemical vapor deposition for perovskite solar cells

2020 ◽  
Vol 13 (7) ◽  
pp. 1997-2023 ◽  
Author(s):  
James A. Raiford ◽  
Solomon T. Oyakhire ◽  
Stacey F. Bent
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Atomic Layer Deposition ◽  
Vapor Deposition ◽  
Perovskite Solar Cells ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Layer Deposition

A review on the versatility of atomic layer deposition and chemical vapor deposition for the fabrication of stable and efficient perovskite solar cells.

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