In-Situ Observation of High Deposition Rate Hydrogenated Polymorphous Silicon Cell Degradation through Variable Intensity Method Measurements

2009 ◽  
Vol 1153 ◽  
Author(s):  
Erik V Johnson ◽  
Ka-Hyun Kim ◽  
Pere Roca i Cabarrocas
Keyword(s):  
Solar Cells ◽  
Deposition Rate ◽  
High Growth ◽  
High Growth Rate ◽  
Open Circuit ◽  
High Rate ◽  
In Situ Observation ◽  
High Deposition Rate ◽  
Degradation Behaviour ◽  
Variable Intensity

AbstractThe efficiencies of hydrogenated polymorphous silicon (pm-Si:H) solar cells have been previously demonstrated to show superior stability under light-soaking. This stability arises due to the fact that the decrease they show in fill factor (FF) is partially offset by an accompanying increase in open circuit voltage (VOC). Recently, high-deposition rate (9Å/s) pm-Si:H material deposited by standard RF-PECVD at 13.56MHz has been investigated as the intrinsic layer in photovoltaic modules as it has shown excellent electronic properties. The degradation behaviour of these high-deposition rate cells, however, differs significantly from that of lower deposition rate material. In particular, no beneficial increase in Voc is observed during light soaking. We investigate the degradation dynamics of solar cells made from this high growth rate material using a Variable Illumination Method (VIM) during light soaking to quantify the changes to these high-rate cells during light-soaking and directly contrast them with those of low-rate (1.5Å/s) cells. In particular, we discuss the importance of bulk recombination effects vs interface quality changes, as well as the dynamics of changes in VOC.

Control of Materials and Interfaces in μc-Si:H-based Solar Cells Grown at High Rate

2011 ◽  
Vol 1321 ◽  
Author(s):  
Yasushi Sobajima ◽  
Chitose Sada ◽  
Akihisa Matsuda ◽  
Hiroaki Okamoto
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Film Growth ◽  
Defect Density ◽  
Density Measurement ◽  
High Growth ◽  
High Growth Rate ◽  
High Rate ◽  
Bulk Region ◽  
Dangling Bond

ABSTRACTGrowth process of microcrystalline silicon (μc-Si:H) using plasma-enhanced chemicalvapor- deposition method under high-rate-growth condition has been studied for the control of optoelectronic properties in the resulting materials. We have found two important things for the spatial-defect distribution in the resulting μc-Si:H through a precise dangling-bond-density measurement, e. g., (1) dangling-bond defects are uniformly distributed in the bulk region of μc- Si:H films independent of their crystallite size and (2) large number of dangling bonds are located at the surface of μc-Si:H especially when the film is deposited at high growth rate. Starting procedure of film growth has been investigated as an important process to control the dangling-bond-defect density in the bulk region of resulting μc-Si:H through the change in the electron temperature by the presence of particulates produced at the starting period of the plasma. Deposition of Si-compress thin layer on μc-Si:H grown at high rate followed by thermal annealing has been proposed as an effective method to reduce the defect density at the surface of resulting μc-Si:H. Utilizing the starting-procedure-controlling method and the compress-layerdeposition method together with several interface-controlling methods, we have demonstrated the fabrication of high conversion-efficiency (9.27%) substrate-type (n-i-p) μc-Si:H solar cells whose intrinsic μc-Si:H layer is deposited at high growth rate of 2.3 nm/sec.

Study of Large Area a-Si:H and nc-Si:H Based Multijunction Solar Cells and Materials

2008 ◽  
Vol 1066 ◽  
Author(s):  
Xixiang Xu ◽  
Baojie Yan ◽  
Dave Beglau ◽  
Yang Li ◽  
Greg DeMaggio ◽  
...  
Keyword(s):  
Solar Cells ◽  
Deposition Rate ◽  
Plasma Deposition ◽  
Nanocrystalline Silicon ◽  
High Rate ◽  
High Deposition Rate ◽  
Large Area ◽  
Very High Frequency ◽  
Spatial Uniformity ◽  
Double Junction

ABSTRACTSolar cells based on hydrogenated nanocrystalline silicon (nc-Si:H) have demonstrated significant improvement in the last few years. From the standpoint of commercial viability, good quality nc-Si:H films must be deposited at a high rate. In this paper, we present the results of our investigations on obtaining high quality nc-Si:H and a-Si:H films and solar cells over large areas using high deposition rate. We have employed the modified very high frequency (MVHF) glow discharge technique to realize high-rate deposition. Modeling studies were conducted to attain good spatial uniformity of electric field over a large area (15”×1”) MVHF cathode for nc-Si:H deposition. A comparative study has been carried out between the RF and MVHF plasma deposited a-Si:H and nc-Si:H single-junction and a-Si:H/nc-Si:H double-junction solar cells. By optimizing the nc-Si:H cell and the tunnel/recombination junctions, we have obtained an initial aperture-area (460 cm2) efficiency of 11.9% for a-Si:H/nc-Si:H double-junction cells using conventional RF (13.56 MHz) plasma deposition. The deposition rate was 3 Å/sec. Results on solar cells made with MVHF will also be presented.

Controlling Structural Evolution by VHF Power Profiling Technique for High-efficiency Microcrystalline Silicon Solar Cells at High Deposition Rate

2009 ◽  
Vol 1153 ◽  
Author(s):  
Guofu Hou ◽  
Xiaoyan Han ◽  
Changchun Wei ◽  
Xiaodan Zhang ◽  
Guijun Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Deposition Rate ◽  
High Efficiency ◽  
Structural Evolution ◽  
High Rate ◽  
High Deposition Rate ◽  
Microcrystalline Silicon ◽  
Solar Cell Performance ◽  
Power Profiling

AbstractHigh rate deposition of hydrogenated microcrystalline silicon (μc-Si:H) films and solar cells were prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) process in a high power and high pressure regime. The experiment results demonstrate that in high-rate deposited μc-Si:H films, the structural evolution is much more dramatic than that in low-rate deposited μc-Si:H films. A novel VHF power profiling technique, which was designed by dynamically decreasing the VHF power step by step during the deposition of μc-Si:H intrinsic layers, has been developed to control the structural evolution along the growth direction. Another advantage of this VHF power profiling technique is the reduced ion bombardments on growth surface because of decreasing the VHF power. Using this method, a significant improvement in the solar cell performance has been achieved. A high conversion efficiency of 9.36% (Voc=542mV, Jsc=25.4mA/cm2, FF=68%) was obtained for a single junction μc-Si:H p-i-n solar cell with i-layer deposited at deposition rate over 10 �/s.

High-deposition rate a-Si:H n–i–p solar cells grown by HWCVD

2001 ◽  
Vol 395 (1-2) ◽  
pp. 292-297 ◽  
Author(s):  
Brent P Nelson ◽  
Eugene Iwaniczko ◽  
A.Harv Mahan ◽  
Qi Wang ◽  
Yueqin Xu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Deposition Rate ◽  
High Deposition Rate

Correlation between Powder in the Plasma and Stability of High Rate Deposited a-Si:H

2005 ◽  
Vol 862 ◽  
Author(s):  
Guozhen Yue ◽  
Gautam Ganguly ◽  
Baojie Yan ◽  
Jeffrey Yang ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Light Intensity ◽  
Scattered Light ◽  
Scattered Light Intensity ◽  
High Rate ◽  
Invasive Technique ◽  
High Deposition Rate ◽  
Very High Frequency ◽  
Silicon Photodiode ◽  
Non Invasive

AbstractHydrogenated amorphous silicon (a-Si:H) solar cells incorporating high deposition rate (8-10Å/s) intrinsic layers were deposited using modified very high frequency (MVHF) plasma. We have monitored the light scattered from powder generated in the plasma using an Ar-laser and a silicon photodiode. This simple, non-invasive technique allows us to make measurements on the same reactor used to make the solar cells. First, we have varied the total flow rate and observed a maximum in the scattered light intensity from powder in the plasma during the deposition of the intrinsic layer, and correlated this with the degradation, as well as the stabilized performance of the solar cells. Then, we have studied the effects of varying the deposition temperature and/or the addition of germane to the gas mixture on the scattered light intensity due to powder in the plasma.

Guiding Principle to Develop Intrinsic Microcrystalline Silicon Absorber Layer For Solar Cell By Hot-Wire Cvd

2001 ◽  
Vol 664 ◽  
Author(s):  
A. R. Middya ◽  
U. Weber ◽  
C. Mukherjee ◽  
B. Schroeder
Keyword(s):  
Growth Rate ◽  
Solar Cell ◽  
Cell Structure ◽  
Short Circuit ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Open Circuit ◽  
Hot Wire ◽  
Microcrystalline Silicon

ABSTRACTWe report on ways to develop device quality microcrystalline silicon (μc-Si:H) intrinsic layer with high growth rate by hot-wire chemical vapor deposition (HWCVD). With combine approach of controlling impurities and moderate H-dilution [H2/SiH4 ͌ 2.5], we developed, for the first time, highly photosensitive (103 μc-Si:Hfilms with high growth rate (>1 nm/s); the microstructure of the film is found to be close to amorphous phase (fc ͌ 46 ̻± 5%). The photosensitivity systematically decreases with fc and saturates to 10 for fc> 70%. On application of these materials in non-optimized pin [.proportional]c-Si:H solar cell structure yields 700 mV open-circuit voltage however, surprisingly low fill factor and short circuit current. The importance of reduction of oxygen impurities [O], adequate passivation of grain boundary (GB) as well as presence of inactive GB of (220) orientation to achieve efficient [.proportional]c-Si:H solar cells are discussed.

Impact of Deposition Rate on the Structural and Magnetic Properties of Sputtered Ni/Cu Multilayer Thin Films

2017 ◽  
Vol 73 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Ali Karpuz ◽  
Salih Colmekci ◽  
Hakan Kockar ◽  
Hilal Kuru ◽  
Mehmet Uckun
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Deposition Rate ◽  
High Rate ◽  
Cubic Phase ◽  
High Deposition Rate ◽  
Multilayer Thin Films ◽  
Face Centered Cubic ◽  
Deposition Rates ◽  
Cu Films

AbstractThe structural and corresponding magnetic properties of Ni/Cu films sputtered at low and high deposition rates were investigated as there is a limited number of related studies in this field. 5[Ni(10 nm)/Cu(30 nm)] multilayer thin films were deposited using two DC sputtering sources at low (0.02 nm/s) and high (0.10 nm/s) deposition rates of Ni layers. A face centered cubic phase was detected for both films. The surface of the film sputtered at the low deposition rate has a lot of micro-grains distributed uniformly and with sizes from 0.1 to 0.4 μm. Also, it has a vertical acicular morphology. At high deposition rate, the number of micro-grains considerably decreased, and some of their sizes increased up to 1 μm. The surface of the Ni/Cu multilayer deposited at the low rate has a relatively more grainy and rugged structure, whereas the surface of the film deposited at the high rate has a relatively larger lateral size of surface grains with a relatively fine morphology. Saturation magnetisation, Ms, values were 90 and 138 emu/cm3 for deposition rates of 0.02 and 0.10 nm/s, respectively. Remanence, Mr, values were also found to be 48 and 71 emu/cm3 for the low and high deposition rates, respectively. The coercivity, Hc, values were 46 and 65 Oe for the low and high Ni deposition rates, respectively. The changes in the film surfaces provoked the changes in the Hc values. The Ms, Mr, and Hc values of the 5[Ni(10 nm)/Cu(30 nm)] films can be adjusted considering the surface morphologies and film contents caused by the different Ni deposition rates.

High rate growth of device grade silicon thin films for solar cells

2001 ◽  
Vol 664 ◽  
Author(s):  
M. Kondo ◽  
S. Suzuki ◽  
Y. Nasuno ◽  
A. Matsuda
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Defect Density ◽  
Chemical Vapor ◽  
High Growth ◽  
Ion Bombardment ◽  
High Rate ◽  
Limiting Factors ◽  
Material Quality ◽  
Deuterium Dilution

ABSTRACTWe have developed a plasma enhanced chemical vapor deposition (PECVD) technique for high-rate growth of µc-Si:H at low temperatures using hydrogen diluted monosilane source gas under high-pressure depletion conditions. It was found that material qualities deteriorate, e.g. crystallinity decreases and defect density increases with increasing growth rate mainly due to ion damage from the plasma. We have found that deuterium dilution improves not only the crystallinity but also defect density as compared to hydrogen dilution and that deuterium to hydrogen ratio incorporated in the film has a good correlation with crystallinity. The advantages of the deuterium dilution are ascribed to lower ion bombardment due to slower ambipolar diffusion of deuterium ion from the plasma. Further improvement of material quality has been achieved using a triode technique where a mesh electrode inserted between cathode and anode electrodes prevents from ion bombardment. In combination with a shower head cathode, the triode technique remarkably improves the crystallinity as well as defect density at a high growth rate. As a consequence, we have succeeded to obtain much better crystallinity and uniformity at 5.8 nm/s with a defect density of 2.6×1016cm−3. We also discuss the limiting factors of growth rate and material quality for µc-Si solar cells.

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