The Advantages of Ga-Graded Obtained by Growth Profile Modification and Na Incorporation on Cu(In,Ga)Se2 Solar Cells

2014 ◽  
Vol 936 ◽  
pp. 633-638
Author(s):  
Rachsak Sakdanuphab ◽  
Sojiphong Chatraphorn ◽  
Kajornyod Yoodee
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Band Gap ◽  
Structural Property ◽  
Growth Process ◽  
Optical Transmission ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Growth Profile

Cu (In,Ga)Se2 (CIGS) compound is a p-type semiconductor that has been used as light absorber layer in high efficiency thin film solar cell. The CIGS compound can be adjusted the band gap energy by varying the ratio of [Ga]/([In]+[Ga]) ratio (x). From theoretical and simulation, it was found that band gap grading in CIGS thin films showed the advantages to increase the efficiency of solar cells. Generally, the band gap grading can be done by the growth of non homogeneous x-ratio in depth of CIGS thin films. In this work, we develop two approaches to create band gap grading in CIGS thin films; (1) modifying the growth profile and (2) using Na incorporation in the growth process. The effects of Ga-graded would be revealed and compared with homogeneous CIGS thin films. CIGS thin films were grown on soda-lime glass and Al2O3 coated soda-lime glass substrates by molecular beam deposition method. The growth process was based on 2-stage and 3-stage growth profiles. The as grown films were characterized for their structural property, chemical composition and optical transmission as well as solar cell performance. The Auger electron spectroscopy in depth profiles revealed the variation of x-ratio increasing from the surface toward the back contact in CIGS films with our modified growth profile and Na incorporation. This result indicated Ga-graded in CIGS thin films. The structural property of Ga-graded CIGS films showed the (112) preferred orientation of the chalcopyrite structure with a broad asymmetric spectrum related to the inhomogeneous structure. The optical transmission measurements of the Ga-graded CIGS film showed the broad transition near the absorption edge indicating the effect of the band gap grading as a result of the variation in depth of the Ga-content. From I-V measurements, the solar cell efficiencies significantly increase due to the advantages of Ga-graded constitute.

Optical and Electrical Analyses of Thallium Sulphide Thin Films

2021 ◽  
Vol 14 (3) ◽  
pp. 249-253
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Soda Lime ◽  
High Energy ◽  
Window Layer ◽  
Soda Lime Glass ◽  
Energy Band Gap ◽  
Thallium Chloride ◽  
Light Region ◽  
Silicon And Germanium

Abstract: In this paper, suitability of thallium sulphide films were investigated as an alternative to conventional silicon and germanium that were used as window layers in solar cells. Thin films were deposited on soda lime glass (SLG) substrates in a chemical bath containing Thallium Chloride (TlCl2) and Thiourea (NH2)2CS which was conditioned at 80 ºC for about 5 hours to deposit the films. Effects of annealing on the film samples at 300 ºC and 350 ºC were studied respectively by use of UV-VIS Avantes electrophotometer and Four-Point-Probe (FPP) machine in the light region with wavelength range from 200 nm to 1000 nm. The results obtained suggest that the thin films obtained are good materials for optoelectronics. The absorption spectra exhibited a relatively high energy band-gap. Materials of this nature are good for window layers which serve as passage to the absorber layer where needed charge carriers are produced. Keywords: Thin film, Thallium Sulphide, Window layer, Optoelectronics, Solar cells.

Cu(In,Ga)Se2 Prepared from Electrodeposited CuGaSe2/CuInSe2 Bilayer for Solar Cell Applications

2007 ◽  
Vol 1012 ◽  
Author(s):  
Yusuke Oda ◽  
Takashi Minemoto ◽  
Hideyuki Takakura ◽  
Yoshihiro Hamakawa
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Supporting Electrolyte ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Cigs Solar Cell ◽  
Diode Behavior

AbstractWe report the preparation of Cu(In,Ga)Se2 (CIGS) thin-films using the electrodeposited (ED) CuGaSe2 (CGS)/CuInSe2 (CIS) bilayers. CGS/CIS bilayers were prepared on soda-lime glass /Mo substrates to realize the controlled Ga/(Ga+In) ratios and smooth layers of CIGS thin-films. It was found that the composition and morphology of CGS films was highly dependent on the composition of the bath. Crack-free and morphological CGS thin-films were obtained by the addition of supporting electrolyte and brightener. For the morphology and the crystallization of the ED-CIGS films, the best electric charges of CGS and CIS films were 1.0 C and 6.0 C respectively and the films were annealed at 600 oC for 60 min. However, the interface of the ED-CGS/CIS film had some voids and interdiffusions of Ga and In did not take place by annealing. The CIGS solar cell using ED-CGS/CIS films as an absorber exhibited diode behavior.

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.

scholarly journals Optimization of Mo/Cr bilayer back contacts for thin-film solar cells

2018 ◽  
Vol 9 ◽  
pp. 2700-2707 ◽  
Author(s):  
Nima Khoshsirat ◽  
Fawad Ali ◽  
Vincent Tiing Tiong ◽  
Mojtaba Amjadipour ◽  
Hongxia Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Single Layer ◽  
Soda Lime ◽  
Thin Film Solar Cells ◽  
Soda Lime Glass ◽  
Tin Sulfide ◽  
Back Contact ◽  
Bilayer Films

Molybdenum (Mo) is the most commonly used material as back contact in thin-film solar cells. Adhesion of Mo film to soda–lime glass (SLG) substrate is crucial to the performance of solar cells. In this study, an optimized bilayer structure made of a thin layer of Mo on an ultra-thin chromium (Cr) adhesion layer is used as the back contact for a copper zinc tin sulfide (CZTS) thin-film solar cell on a SLG substrate. DC magnetron sputtering is used for deposition of Mo and Cr films. The conductivity of Mo/Cr bilayer films, their microstructure and surface morphology are studied at different deposition powers and working pressures. Good adhesion to the SLG substrate has been achieved by means of an ultra-thin Cr layer under the Mo layer. By optimizing the deposition conditions we achieved low surface roughness, high optical reflectance and low sheet resistivity while we could decrease the back contact thickness to 600 nm. That is two thirds to half of the thickness that is currently being used for bilayer and single layer back contact for thin-film solar cells. We demonstrate the excellent properties of Mo/Cr bilayer as back contact of a CZTS solar cell.

Fabrication of Cu2ZnSn(S,Se)4 solar cells by printing and high-pressure sintering process

2013 ◽  
Vol 1538 ◽  
pp. 179-183 ◽  
Author(s):  
Feng Gao ◽  
Tsuyoshi Maeda ◽  
Takahiro Wada
Keyword(s):  
Solid Solution ◽  
High Pressure ◽  
Solar Cells ◽  
Solar Cell ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Sintering Process ◽  
Device Structure ◽  
Gas Atmosphere ◽  
High Pressure Sintering

ABSTRACTWe fabricated Cu2ZnSn(SxSe1-x)4 (CZTSSe) solar cells by a printing and high-pressure sintering (PHS) process. First, the CZTSSe solid solution powders were synthesized by heating the elemental mixtures at 550oC for 5 h in an N2 gas atmosphere. We fabricated CZTSSe films by a printing and high-pressure sintering (PHS) process. The obtained dense CZTSSe film was post-annealed at 550oC for 10 min under an N2 +5% H2S gas atmosphere. We fabricated CZTSSe solar cells with the device structure of Ag/ITO/i-ZnO/CdS/CZTSSe/Mo/soda-lime glass. The CZTSSe solar cell showed an efficiency of 2.1%, with Voc of 272 mV, Jsc of 18.0 mA/cm2 and FF of 0.44.

Ge-alloyed CZTSe thin film solar cell using molecular precursor adopting spray pyrolysis approach

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 37621-37627 ◽  
Author(s):  
Dhruba B. Khadka ◽  
SeongYeon Kim ◽  
JunHo Kim
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Band Gap ◽  
Spray Pyrolysis ◽  
Thin Film Solar Cell ◽  
Molecular Precursors ◽  
Molecular Precursor

We report a promising fabrication approach for the synthesis of Ge-alloyed Cu2Zn(GexSn1−x)Se4 (CZGTSe) thin films using molecular precursors by spray pyrolysis to obtain band gap tuned kesterite solar cells.

scholarly journals Synthesis of simple, low cost and benign sol–gel Cu2InxZn1−xSnS4alloy thin films: influence of different rapid thermal annealing conditions and their photovoltaic solar cells

RSC Advances ◽  
2018 ◽  
Vol 8 (17) ◽  
pp. 9038-9048 ◽  
Author(s):  
Yingrui Sui ◽  
Yanjie Wu ◽  
Yu Zhang ◽  
Fengyou Wang ◽  
Yanbo Gao ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Rapid Thermal Annealing ◽  
Low Cost ◽  
Sol Gel ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Annealing Conditions ◽  
Rapid Annealing ◽  
Photovoltaic Solar Cells

Cu2InxZn1−xSnS4(x= 0.4) alloy thin films were synthesized on soda lime glass (SLG) substrate by a simple low-cost sol–gel method followed by a rapid annealing technique.

Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques

2015 ◽  
Vol 15 (10) ◽  
pp. 7722-7726 ◽  
Author(s):  
Min Jung Kim ◽  
Jihye Lee ◽  
Seon Hee Kim ◽  
Haidong Kim ◽  
Kang-Bong Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Trace Elements ◽  
Solar Cell ◽  
Flexible Substrate ◽  
Analytical Techniques ◽  
Soda Lime ◽  
Average Concentration ◽  
Soda Lime Glass ◽  
Matrix Elements ◽  
Trace Impurities

Chalcopyrite Cu(In,Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In,Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT.

Characterization of Cu(In,Ga)3Se5 Thin Film for Top Cell in CIGS Tandem Solar Cells

2007 ◽  
Vol 124-126 ◽  
pp. 959-962 ◽  
Author(s):  
Ki Hwan Kim ◽  
Byung Tae Ahn ◽  
Se Han Kwon ◽  
Jae Ho Yun ◽  
Kyung Hoon Yoon
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Hole Concentration ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Soda Lime Glass Substrate ◽  
Tandem Solar Cells ◽  
Cu Content ◽  
Cell Efficiency ◽  
Ga Content

Cu(In,Ga)3Se5 films were deposited on soda-lime glass substrate by three-stage co-evaporation process. In the film, the band gap increased as the Cu content decreased and also as the Ga content increased. The grain size became smaller as the Ga content increased. In the Cu1.29(In1-xGax)3Se5 system, the maximum hole concentration was 1x1015 /cm3 when the Ga content was 0.5 and its band gap was 1.45 eV. Comparing the conventional CIGS solar cell with Cu0.8(In0.7Ga0.3)Se2 film, the series resistance is too large, indicating that further p-type doping in the Cu(In,Ga)3Se5 film is necessary to improve cell efficiency for the top cell application in CIGS tandem solar cells.

Effect of Heat Treatment on the Crystal Structure and Optical Band Gap of Cigs Thin Films

2011 ◽  
Vol 347-353 ◽  
pp. 94-97
Author(s):  
Lei Han ◽  
Tie Zhu Ding ◽  
Yan Lai Wang ◽  
Luo Meng Chao ◽  
Tao Shang
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Heat Treatment ◽  
Band Gap ◽  
Soda Lime ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Soda Lime Glass ◽  
Glass Substrates ◽  
Crystallization Conditions

The CIGS thin films were prepared on ordinary soda lime glass substrates by pulsed laser deposition (PLD). The XRD and UV-visible spectrophotometer has been determined. The influence of different heat treatment temperature on crystal structure and optical properties has been studied. The results shows that heat treatment at 450°C, the films along the (112) plane preferential grow. The thin film’s structure is integrity, the film is in best crystallization conditions, band gap is 1.35eV and the film has a high visible light absorption efficiency.

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