Several Efficiency Influencing Factors In CdTe/CdS Solar Cells

1997 ◽  
Vol 485 ◽  
Author(s):  
K. Li ◽  
Z. C. Feng ◽  
A. T. S. Wee ◽  
H. C. Chou ◽  
J. Y. Lin ◽  
...  

AbstractSeveral efficiency influencing factors in MOCVD-grown CdTe/CdS solar cells, including preferential crystal orientation of CdTe layers, CdTe grain size and surface roughness, interfacial mixing, and surface and interface geometrical morphology, are studied. X-ray diffraction (XRD) shows that polycrystalline CdTe/CdS solar cells with higher efficiencies tend to have more (111) planes of CdTe parallel to the macro-surface. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis reveal the relationship between the grain size/surface roughness and cell efficiency. Secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES) depth profiling show that the interfacial geometrical morphology has a significant influence on the efficiency of CdTe/CdS solar cells. Finally it is shown that interfacial mixing reduces the number of interfacial states and recombination centers and the energy loss due to internal reflectance, enhancing the performance of the solar cells.

1996 ◽  
Vol 428 ◽  
Author(s):  
G. O. Ramseyer ◽  
L. H. Walsh ◽  
J. V. Beasock ◽  
H. F. Helbig ◽  
R. C. Lacoe ◽  
...  

AbstractPatterned 930 nm Al(1%-Si) interconnects over 147 nm of Cu were electromigration lifetime tested at 1.0–1.5 × 105 A/cm2 at 250 °C. The morphology of the surfaces of the electromigrated stripes with different line widths and times to failure were characterized by atomic force microscopy, and changes in surface roughness were compared. The diffusion of copper into the electromigrated aluminum stripes was determined by depth profiling using Auger electron spectroscopy. In particular, areas where hillocks formed were examined and compared to areas of median roughness.


1994 ◽  
Vol 336 ◽  
Author(s):  
H.N. Wanka ◽  
E. Lotter ◽  
M.B. Schubert

ABSTRACTThe chemical reactions at the surface of transparent conductive oxides (SnO2, ITO and ZnO) have been studied in silane and hydrogen plasmas by in-situ ellipsometry and by SIMS as well as XPS depth profiling. SIMS and XPS of the interface reveal an increasing amount of metallic phases upon lowering a-Si:H growth rates (controlled by plasma power), indicating that the ion and radical impact is more than compensated by protecting the surface by a rapidly growing a-Si:H film. Hence, optical transmission of TCO films as well as the efficiency of solar cells can be improved if the first few nanometers of the p-layer are grown at higher rates. Comparing a-Si:H deposition on top of different TCOs, reduction effects on ITO and SnO2 have been detected whereas ZnO appeared to be chemically stable. Therefore an additional shielding of the SnO2 surface by a thin ZnO layer has been investigated in greater detail. Small amounts of H are detected close to the ZnO surface by SIMS after hydrogen plasma treatment, but no significant changes occur to the optical and electrical properties. In-situ ellipsometry indicates that a ZnO layer as thin as 20 nm completely protects SnO2 from being reduced to metallic phases. This provides for shielding of textured TCOs, and hence rising solar cell efficiencies, too. Regarding light trapping efficiency we additionally investigated the smoothing of initial TCO texture when growing a-Si:H on top by combining atomic force microscopy and spectroscopie ellipsometry.


1996 ◽  
Vol 439 ◽  
Author(s):  
S. Han ◽  
K. H. Yoon ◽  
K. H. Kim ◽  
H. G. Jang ◽  
S. C. Choi ◽  
...  

AbstractCopper films on Si(100) were prepared by partially ionized beam at 0 kV and 3 kV acceleration voltages in order to investigate effects of ion energy on electrical property with thickness. X-ray diffraction(XRD) pattern analysis was used to investigate crystallinity of the copper films, microstructure by Scanning electron microscope(SEM) and surface roughness by atomic force microscopy(AFM). The crystallinity of the copper films grown at the 3 kV was more (111) textured than that at the 0 kV. The copper films grown at the both conditions had nearly same grain size below a thickness of 1000 Å. The 1800 Å Cu film grown at the 3 kV was 3 times rough than that at the 0 kV. The resistivity of copper films increased due to surface and grain boundary scattering, and the change of resistivity was discussed in terms of surface roughness, grain size and film density assisted by average depositing energy.


Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
J. Ying Chyi Liew ◽  
Zainal Talib ◽  
W. Mahmood ◽  
M. Yunus ◽  
Zulkarnain Zainal ◽  
...  

AbstractThin films of copper selenide (CuSe) were physically deposited layer-by-layer up to 5 layers using thermal evaporation technique onto a glass substrate. Various film properties, including the thickness, structure, morphology, surface roughness, average grain size and electrical conductivity are studied and discussed. These properties are characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ellipsometer and 4 point probe at room temperature. The dependence of electrical conductivity, surface roughness, and average grain size on number of layers deposited is discussed.


1996 ◽  
Vol 438 ◽  
Author(s):  
S. Han ◽  
K. H. Yoon ◽  
K. H. Kim ◽  
H. G. Jang ◽  
S. C. Choi ◽  
...  

AbstractCopper films on Si(100) were prepared by partially ionized beam at 0 kV and 3 kV acceleration voltages in order to investigate effects of ion energy on electrical property with thickness. X-ray diffraction(XRD) pattern analysis was used to investigate crystallinity of the copper films, microstructure by Scanning electron microscope(SEM) and surface roughness by atomic force microscopy(AFM). The crystallinity of the copper films grown at the 3 kV was more (111) textured than that at the 0 kW. The copper films grown at the both condiitions had nearly same grain size below a thickness of 1000 Å. The 1800 Å Cu film grown at the 3 kV was 3 times rough than that at the 0 kV. The resistivity of copper films increased due to surface and grain boundary scattering, and the change of resistivity was discussed in terms of surface roughness, grain size and film density assisted by average depositing energy.


Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Daniel HaÅ¡ko ◽  
Jaroslav Bruncko ◽  
Andrej Vincze ◽  
František Uherek

AbstractTwo series of polycrystalline zinc oxide (ZnO) layers, from Zn or ZnO targets, were grown on silicon (1 1 1) substrates by pulsed laser deposition (PLD) at ambient oxygen pressure levels, stepwise increased from 1 to 35 Pa. For ablation of targets, a pulsed Nd:YAG laser was used. The structural and morphological properties of the layers were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS). The SEM images of ZnO layers in SE mode show a uniform granular structure and modified surface morphology, depending on oxygen pressure. The mean grain size in height and lateral directions decreases with an increase of oxygen pressure from 1 to 5 Pa, while a subsequent rise of oxygen pressure from 5 to 35 Pa will cause an increase in the grain size. The AFM measurement revealed that the surface structures of zinc oxide layers grown from different targets were similar, and the layers formed at an ambient oxygen pressure of 5 Pa exhibited the smallest values of calculated roughness and granularity. SIMS depth profiling analyses confirmed that the ZnO composition was homogenous across the layer, up to the abrupt change of chemical composition at the interface between the ZnO layer and the Si substrate.


2021 ◽  
Vol 59 (1) ◽  
pp. 67-72
Author(s):  
Kwangbae Kim ◽  
Ohsung Song

The properties of 6 mM urea added perovskite solar cells (PSCs) according to ZrO2 electron transport layer (ETL) thicknesses of 204, 221, 254, and 281 nm were examined. A solar simulator was used to characterize the photovoltaic properties of the cell. Optical microscopy and field emission scanning electron microscope were used for the microstructure analysis, and a 3D profiler was used to analyze surface roughness. UV-VIS-NIR was used to analyze transmittance. From the photovoltaic analysis result, an energy conversion efficiency (ECE) of 14.93% was exhibited by the cell with a 221 nm-ZrO2 layer and added urea. From the analysis result of microstructure and surface roughness, 384 nm grain size was obtained through appropriate surface roughness of base layer for perovskite growth and the grain size coarsening by the urea under the 221 nm-ZrO2 condition. For this reason, ECE increased as the resistance of the grain boundary decreased. When the thickness of the ETL was increased above 250 nm-ZrO2, the ECE decreased due to the reduction in light transmittance, and light reaching the perovskite layer. Therefore, the ECE of PCS could be enhanced by selecting a ZrO2 layer with the appropriate thickness and the addition of urea.


CrystEngComm ◽  
2020 ◽  
Vol 22 (16) ◽  
pp. 2718-2727 ◽  
Author(s):  
Methawee Nukunudompanich ◽  
Gekko Budiutama ◽  
Kazuma Suzuki ◽  
Kei Hasegawa ◽  
Manabu Ihara

The surface roughness of the c-TiO2 layer help controls the perovskite grain size without any other parameter. The direct effect of perovskite grain size on PSC performance is clarified.


2014 ◽  
Vol 13 (03) ◽  
pp. 1450020 ◽  
Author(s):  
Ştefan Ţălu ◽  
Sebastian Stach ◽  
Muhammad Ikram ◽  
Dinesh Pathak ◽  
Tomas Wagner ◽  
...  

The objective of this work is to quantitatively characterize the 3D complexity of ZnO : TiO 2-organic blended solar cells layers by atomic force microscopy and fractal analysis. ZnO : TiO 2-organic blended solar cells layers were investigated by AFM in tapping-mode in air, on square areas of 25 μm2. A detailed methodology for ZnO : TiO 2-organic blended solar cells layers surface fractal characterization, which may be applied for AFM data, is presented. Detailed surface characterization of the surface topography was obtained using statistical parameters, according with ISO 25178-2: 2012. The fractal dimensions Df values (all with average ± standard deviation), obtained with morphological envelopes method, for: blend D1 ( P 3 HT : PCBM : ZnO : TiO 2 blend with ratio 1:0.35:0.175:0.175 mg in 1 ml of Chlorobenzene) is Df = 2.55 ± 0.01; and for blend D2 ( P 3 HT : PCBM : ZnO : TiO 2 blend with ratio 1:0.55:0.075:0.075 mg in 1 ml of Chlorobenzene) is Df = 2.45 ± 0.01. Denoting the ratios in 1 ml of Chlorobenzene with D1 and D2 articles. The 3D surface roughness of samples revealed a fractal structure at nanometer scale. Fractal and AFM analysis may assist manufacturers in developing ZnO : TiO 2-organic blended solar cells layers with better surface characteristics and provides different yet complementary information to that offered by traditional surface statistical parameters.


2008 ◽  
Vol 6 (31) ◽  
pp. 159-168 ◽  
Author(s):  
Chengtie Wu ◽  
Yogambha Ramaswamy ◽  
Xuanyong Liu ◽  
Guocheng Wang ◽  
Hala Zreiqat

Novel Ca-Si-Ti-based sphene (CaTiSiO 5 ) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study was to prepare sphene coating on titanium alloy (Ti-6Al-4V) for orthopaedic applications using the plasma spray method. The phase composition, surface and interface microstructure, coating thickness, surface roughness and bonding strength of the plasma-sprayed sphene coating were analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and the standard mechanical testing of the American Society for Testing and Materials, respectively. The results indicated that sphene coating was obtained with a uniform and dense microstructure at the interface of the Ti-6Al-4V surface and the thickness and surface roughness of the coating were approximately 150 and 10 μm, respectively. Plasma-sprayed sphene coating on Ti-6Al-4V possessed a significantly improved bonding strength and chemical stability compared with plasma-sprayed hydroxyapatite (HAp) coating. Plasma-sprayed sphene coating supported human osteoblast-like cell (HOB) attachment and significantly enhanced HOB proliferation and differentiation compared with plasma-sprayed HAp coating and uncoated Ti-6Al-4V. Taken together, plasma-sprayed sphene coating on Ti-6Al-4V possessed excellent bonding strength, chemical stability and cellular bioactivity, indicating its potential application for orthopaedic implants.


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