Characterization of Cu(In,Ga)Se2/Mo Interface in CIGS Solar Cells

1997 ◽  
Vol 485 ◽  
Author(s):  
S. Nishiwaki ◽  
N. Kohara ◽  
T. Negami ◽  
M. Nishitani ◽  
T. Wada
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Soda Lime ◽  
Film Deposition ◽  
Soda Lime Glass ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Current Voltage ◽  
Stage Process ◽  
Cigs Solar Cells

AbstractThe interface between a Cu(In,Ga)Se2 (CIGS) and an underlying Mo layer was studied by X-ray diffraction and high resolution transmission electron microscopy. The CIGS layer was deposited onto Mo coated soda-lime glass using the “3-stage” process. A MoSe2 layer found to form at the CIGS/Mo interface during the 2nd stage of the “3-stage” process. The thickness of the MoSe2 layer depended on the substrate temperature used for CIGS film deposition as well as the Na content of the CIGS and/or Mo layers. For higher substrate temperatures, thicker MoSe2 layers were observed. The Na in the CIGS and/or Mo layer is felt to assist in the formation of MoSe2. Current-Voltage measurements of the heterojunction formed by the CIGS/Mo interface were ohmic even at low temperature. The role of the MoSe2 layer in high efficiency CIGS solar cells is discussed.

Preparation of Cu(In,Ga)Se2 thin films from In–Ga–Se precursors for high-efficiency solar cells

1999 ◽  
Vol 14 (12) ◽  
pp. 4514-4520 ◽  
Author(s):  
S. Nishiwaki ◽  
T. Satoh ◽  
S. Hayashi ◽  
Y. Hashimoto ◽  
T. Negami ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Efficiency ◽  
Soda Lime ◽  
Phase Changes ◽  
Homogeneous Distribution ◽  
Precursor Film ◽  
Soda Lime Glass ◽  
X Ray Diffraction ◽  
High Efficiency Solar Cells ◽  
Transmission Electron

Growth of Cu(In,Ga)Se2 (CIGS) films from In–Ga–Se precursors was characterized by scanning Auger electron spectroscopy (SAES), secondary ion mass spectroscopy (SIMS), x-ray diffraction, scanning electron microscopy, and transmission electron microscopy (TEM). In–Ga–Se precursor layers were deposited on Mo-coated soda-lime glass, and then the layers were exposed to Cu and Se fluxes to form CIGS films. The SIMS and SAES analyses showed a homogeneous distribution of Cu throughout the CIGS films during the deposition of Cu and Se. The phase changes observed in the CIGS films during the deposition of Cu and Se on the In–Ga–Se precursor films were as follows: (In,Ga)2Se3 →[Cu(In,Ga)5Se8] →Cu(In,Ga)3Se5 →Cu(In,Ga)Se2. The grain size increased from the submicron grains of the (In,Ga)2Se3 precursor film to several micrometers in the stoichiometric Cu(In,Ga)Se2 film. A growth model of CIGS crystals is introduced on the basis of the results of TEM observations. CIGS crystals are mainly grown under (In,Ga)-rich conditions in the preparation from In–Ga–Se precursor films.

TEM Studies of High-Efficiency CdTe Solar Cells on Commercial SnO2/Soda-Lime Glass

2005 ◽  
Vol 865 ◽  
Author(s):  
Yanfa Yan ◽  
X. Wu ◽  
J. Zhou ◽  
M.M. Al-Jassim
Keyword(s):  
Solar Cells ◽  
Thin Layer ◽  
High Efficiency ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Back Side ◽  
Cdte Solar Cells ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Weak Diffusion

AbstractThe microstructure of high-efficiency CdTe solar cells on commercial SnO2/soda-lime glass was investigated by scanning transmission electron microscopy. The CdTe solar cells have a structure of soda-lime glass/SnO2/ZTO/CdS:O/CdTe. We found no interdiffusion between the SnO2 layer and ZTO layer. Weak diffusion of Zn from the ZTO layer into the CdS:O layer was observed; however, the diffusion was not uniform. Interdiffusion also occurred at the CdTe/CdS:O interface. In the back-side of the CdTe, a thin layer of Te was found, which formed during the nitric-phosphoric etching. In addition, a very thin layer of CdHgTe was observed at the CdTe/Te interface.

scholarly journals Deposition Technologies of High-Efficiency CIGS Solar Cells: Development of Two-Step and Co-Evaporation Processes

Crystals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 296 ◽  
Author(s):  
Chia-Hua Huang ◽  
Wen-Jie Chuang ◽  
Chun-Ping Lin ◽  
Yueh-Lin Jan ◽  
Yu-Chiu Shih
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Open Circuit ◽  
Film Properties ◽  
Step Process ◽  
Metal Precursors ◽  
Stage Process ◽  
Cigs Solar Cells ◽  
Surface Morphologies ◽  
The Given

The two-step process including the deposition of the metal precursors followed by heating the metal precursors in a vacuum environment of Se overpressure was employed for the preparation of Cu(In,Ga)Se2 (CIGS) films. The CIGS films selenized at the relatively high Se flow rate of 25 Å/s exhibited improved surface morphologies. The correlations among the two-step process parameters, film properties, and cell performance were studied. With the given selenization conditions, the efficiency of 12.5% for the fabricated CIGS solar cells was achieved. The features of co-evaporation processes including the single-stage, bi-layer, and three-stage process were discussed. The characteristics of the co-evaporated CIGS solar cells were presented. Not only the surface morphologies but also the grading bandgap structures were crucial to the improvement of the open-circuit voltage of the CIGS solar cells. Efficiencies of over 17% for the co-evaporated CIGS solar cells have been achieved. Furthermore, the critical factors and the mechanisms governing the performance of the CIGS solar cells were addressed.

scholarly journals Characterization and Analysis of Ultrathin CIGS Films and Solar Cells Deposited by 3-Stage Process

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Grace Rajan ◽  
Krishna Aryal ◽  
Shankar Karki ◽  
Puruswottam Aryal ◽  
Robert W. Collins ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Large Scale ◽  
Open Circuit ◽  
Ex Situ ◽  
Photovoltaic Application ◽  
Current Voltage ◽  
Stage Process ◽  
Cigs Solar Cells ◽  
The Cost

In view of the large-scale utilization of Cu(In,Ga)Se2 (CIGS) solar cells for photovoltaic application, it is of interest not only to enhance the conversion efficiency but also to reduce the thickness of the CIGS absorber layer in order to reduce the cost and improve the solar cell manufacturing throughput. In situ and real-time spectroscopic ellipsometry (RTSE) has been used conjointly with ex situ characterizations to understand the properties of ultrathin CIGS films. This enables monitoring the growth process, analyzing the optical properties of the CIGS films during deposition, and extracting composition, film thickness, grain size, and surface roughness which can be corroborated with ex situ measurements. The fabricated devices were characterized using current voltage and quantum efficiency measurements and modeled using a 1-dimensional solar cell device simulator. An analysis of the diode parameters indicates that the efficiency of the thinnest cells was restricted not only by limited light absorption, as expected, but also by a low fill factor and open-circuit voltage, explained by an increased series resistance, reverse saturation current, and diode quality factor, associated with an increased trap density.

scholarly journals Adhesion Improvement and Characterization of Magnetron Sputter Deposited Bilayer Molybdenum Thin Films for Rear Contact Application in CIGS Solar Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Weimin Li ◽  
Xia Yan ◽  
Armin G. Aberle ◽  
Selvaraj Venkataraj
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Magnetron Sputtering ◽  
Surface Oxidation ◽  
Bottom Layer ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Individual Layer ◽  
Glass Substrates ◽  
Cigs Solar Cells

Molybdenum (Mo) thin films are widely used as rear electrodes in copper indium gallium diselenide (CIGS) solar cells. The challenge in Mo deposition by magnetron sputtering lies in simultaneously achieving good adhesion to the substrates while retaining the electrical and optical properties. Bilayer Mo films, comprising five different thickness ratios of a high pressure (HP) deposited bottom layer and a low pressure (LP) deposited top layer, were deposited on 40 cm × 30 cm soda-lime glass substrates by DC magnetron sputtering. We focus on understanding the effects of the individual layer properties on the resulting bilayer Mo films, such as microstructure, surface morphology, and surface oxidation. We show that the thickness of the bottom HP Mo layer plays a major role in determining the micromechanical and physical properties of the bilayer Mo stack. Our studies reveal that a thicker HP Mo bottom layer not only improves the adhesion of the bilayer Mo, but also helps to improve the film crystallinity along the preferred [110] direction. However, the surface roughness and the porosity of the bilayer Mo films are found to increase with increasing bottom layer thickness, which leads to lower optical reflectance and a higher probability for oxidation at the Mo surface.

Low Temperature Growth of CIGS Thin Films for Flexible Solar Cells

2001 ◽  
Vol 668 ◽  
Author(s):  
D. Rudmann ◽  
F.-J. Haug ◽  
M. Kaelin ◽  
H. Zogg ◽  
A.N. Tiwari ◽  
...  
Keyword(s):  
Solar Cells ◽  
Soda Lime ◽  
Film Deposition ◽  
Soda Lime Glass ◽  
Temperature Growth ◽  
Polymer Substrates ◽  
Cell Efficiency ◽  
A Cell ◽  
Lift Off ◽  
Substrate Temperatures

ABSTRACTLow substrate temperatures have to be used for polymer substrates. Therefore, using soda- lime glass (SLG) substrates with and without an alkali barrier (Al2O3), a three-step CIGS coevaporation process for a substrate temperature of 450 °C has been developed and compared to film deposition with constant evaporation rates. The three-step process was found to enhance grain nucleation. An efficiency of 14.0 % has been achieved with this process for solar cells on SLG. Since polymers in general do not contain Na, a way of Na addition to the absorber is needed. It is shown that NaF coevaporation can be used to control the Na content in CIGS. Also incorporation of Na in CIGS by diffusion from a NaCl layer through a polyimide is demonstrated. With such SLG/NaCl/polyimide structures flexible solar cells can be obtained using a lift-off process. A cell efficiency of 11.6 % (0.99 cm2 area) has been achieved.

Investigation of sputtered Mo layers on soda-lime glass substrates for CIGS solar cells

2012 ◽  
Vol 27 (11) ◽  
pp. 115020 ◽  
Author(s):  
Chia-Hua Huang ◽  
Hung-Lung Cheng ◽  
Wei-En Chang ◽  
Ming Yi Huang ◽  
Yi-Jiunn Chien
Keyword(s):  
Solar Cells ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Glass Substrates ◽  
Cigs Solar Cells

Study of CIGS Solar Cells Back Contact

2007 ◽  
Vol 1012 ◽  
Author(s):  
Sylvain Marsillac ◽  
Himal Khatri
Keyword(s):  
Grain Size ◽  
Soda Lime ◽  
Argon Pressure ◽  
Soda Lime Glass ◽  
X Ray Diffraction ◽  
Bell Curve ◽  
Glass Substrates ◽  
Afm Imaging ◽  
Lower Extent ◽  
Cigs Solar Cells

AbstractMolybdenum thin films were deposited by r.f. magnetron sputtering. The strain in the films was mostly tensile and varied, with the Argon pressure and the r.f. power, along a bell curve, reaching a maximum at 8 mTorr (80 W) and 6 mTorr (100 W). The grain size deduced from the X-Ray diffraction measurements (FWHM) decreased with increasing Argon pressure and, to a lower extent, with decreasing r.f power. The change in grain size, as well as in morphology, was confirmed by AFM imaging. Finally, the resistivity of the films was found to increase with increasing Argon pressure, while the films maintained good adhesion to the soda-lime glass substrates for all Argon pressures and r.f. power.

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