scholarly journals Characteristics of Bilayer Molybdenum Films Deposited Using RF Sputtering for Back Contact of Thin Film Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sea-Fue Wang ◽  
Hsiao-Ching Yang ◽  
Chien-Fong Liu ◽  
Huy-Yun Y. Bor
Keyword(s):  
Solar Cells ◽  
Rf Sputtering ◽  
Bottom Layer ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Deposition Condition ◽  
Metal Contacts ◽  
Working Pressure ◽  
Soda Lime Glass Substrate ◽  
Sputtering Power

Mo films prepared under a single deposition condition seldom simultaneously obtain a low resistivity and a good adhesion necessary for use in solar cells. In order to surmount the obstacle, bilayer Mo films using DC sputtering at a higher working pressure and a lower working pressure have been attempted as reported in the literature. In this study, RF sputtering with different powers in conjunction with different working pressures was explored to prepare bilayer Mo film. The first bottom layer was grown at a RF sputtering power of 30 W and a working pressure of 12 mTorr, and the second top layer was deposited at 100 W and 4.5 mTorr. The films revealed a columnar growth with a preferred orientation along the (110) plane. The bilayer Mo films reported an electrical resistivity of 6.35 × 10−5 Ω-cm and passed the Scotch tape test for adhesion to the soda-lime glass substrate, thereby qualifying the bilayer Mo films for use as back metal contacts for CIGS substrates.

Effects of Radio-Frequency Sputtering Power on Low Temperature Formation of MoS2 Thin Films on Soda-Lime Glass Substrates

2020 ◽  
Vol 20 (8) ◽  
pp. 4892-4898
Author(s):  
Zhenqian Zhao ◽  
Min Yu Yin ◽  
Sang Jik Kwon ◽  
Eou-Sik Cho
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Rf Sputtering ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Soda Lime Glass Substrate ◽  
Glass Substrates ◽  
Radio Frequency Sputtering ◽  
Sputtering Power ◽  
Surface Morphologies

For the realization of the economical and reliable fabrication process of molybdenum disulfide (MoS2) layers, MoS2 thin films were directly formed a on soda-lime glass substrate by RF sputtering and subsequent rapid thermal annealing (RTA) at a temperature range of 400–550 °C. Using scanning electron microscopy and atomic force microscopy, it was possible to investigate more stable surface morphologies of MoS2 layers at lower RF sputtering powers irrespective of the RTA temperature. Even at an RTA temperature of less than 550 °C, the Raman exhibited more distinct E12g and A1g peaks for the MoS2 layers sputtered at lower RF powers. The X-ray photoelectron spectroscopy results revealed that more distinct peaks were observed at a higher RTA temperature, and the peak positions were moved to higher energies at a lower RF sputtering power. Based on the Hall measurements, higher carrier densities were obtained for the MoS2 layers sputtered at lower RF powers.

scholarly journals The Effect of Sputtering Parameters on the Film Properties of Molybdenum Back Contact for CIGS Solar Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Peng-cheng Huang ◽  
Chia-ho Huang ◽  
Mao-yong Lin ◽  
Chia-ying Chou ◽  
Chun-yao Hsu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Signal To Noise Ratio ◽  
Soda Lime ◽  
Structural Features ◽  
Main Peak ◽  
Soda Lime Glass ◽  
Adhesive Tape ◽  
Back Contact ◽  
Working Pressure ◽  
Glass Substrates

Molybdenum (Mo) thin films are widely used as a back contact for CIGS-based solar cells. This paper determines the optimal settings for the sputtering parameters for an Mo thin film prepared on soda lime glass substrates, using direct current (dc) magnetron sputtering, with a metal Mo target, in an argon gas environment. A Taguchi method with an L9orthogonal array, the signal-to-noise ratio, and an analysis of variances is used to determine the performance characteristics of the coating operation. The main sputtering parameters, such as working pressure (mTorr), dc power (W), and substrate temperature (°C), are optimized with respect to the structural features, surface morphology, and electrical properties of the Mo films. An adhesive tape test is performed on each film to determine the adhesion strength of the films. The experimental results show that the working pressure has the dominant effect on electrical resistivity and reflectance. The intensity of the main peak (110) for the Mo film increases and the full width at half maximum decreases gradually as the sputtering power is increased. Additionally, the application of an Mo bilayer demonstrates good adherence and low resistivity.

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.

Effects of Growth Parameters on Surface-morphological, Structural and Electrical Properties of Mo Films by RF Magnetron Sputtering

2008 ◽  
Vol 1123 ◽  
Author(s):  
Shou-Yi Kuo ◽  
Liann-Be Chang ◽  
Ming-Jer Jeng ◽  
Wei-Ting Lin ◽  
Yong-Tian Lu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Film Thickness ◽  
Growth Parameters ◽  
Soda Lime ◽  
Rf Magnetron Sputtering ◽  
Soda Lime Glass ◽  
Working Pressure ◽  
Soda Lime Glass Substrate ◽  
X Ray

AbstractThis work reports on the fabrication and characterization of Mo thin films on soda-lime glass substrate grown by reactive RF magnetron sputtering. Film thickness was measured by x-ray step surface profiler. The structural properties and surface morphology were analyzed by x-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). Electrical properties were measured by four-point probe. It was found that the growth parameters, such as argon flow rate, RF power, film thickness, have significant influences on properties of Mo films. The strain on films revealed the complicated relationship with the working pressure, which might be associated with micro structures and impurities. In order to improve the adhesion and electricity, we adopted a two-pressure deposition scheme. The optimal thickness and sheet resistance are νm and 0.12 ω The mechanisms therein will be discussed in detail. Furthermore, we also investigated the diffusion property of Na ion of double Mo films sputtered on soda-lime glass. Our experimental results could lead to better understanding for improving further CIGS-based photovoltaic devices.

Preparation and Characterization of Cu-Ga-Se Films of Ordered Vacancy Compound

2003 ◽  
Vol 763 ◽  
Author(s):  
S. Nishiwaki ◽  
S. Siebentritt ◽  
M. Ch. Lux-Steiner
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Bottom Layer ◽  
Soda Lime ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Chalcopyrite Structure ◽  
Soda Lime Glass ◽  
Soda Lime Glass Substrate ◽  
Glass Substrates

AbstractCu-Ga-Se films with an orderd vacancy compound (OVC) structure were prepared at substrate temperature about 500 °C by thermal co-deposition. With a preparation under extremely Se excess condition, films of the OVC were synthesized within the compositional ratio of 0.73 ≤ [Ga]/([Cu]+[Ga]) ≤ 0.86 along Cu2Se-Ga2Se3 pseudo binary system. The growth on soda-lime glass substrates improves the crystallinity compared to that on alkali-free glass. An increase in the optical bandgaps of OVC films from 1.85 eV to 1.94 eV was observed with an increase in the Ga content of the films. The deposition of Cu and Se onto Ga2Se3 films resulted in a vertically inhomogeneous film: the bottom layer with the OVC structure and the top layer with the chalcopyrite structure. A solar cell using the CuGa5.0Se8.1 film within a ZnO/CdS/CuGa-Se/Mo/soda-lime glass substrate structure showed an open circuit voltage of 947 mV, an efficiency of 2.2 %, a short circuit current density of 4.5 mA/cm2, and a fill factor of 0.52 (Air Mass 1.5, 0.5 cm2, total area).

Effect of Working Pressure on Structural, Electrical and Optical Properties of CIGS Thin Film Deposited by PLD

2013 ◽  
Vol 768 ◽  
pp. 70-74 ◽  
Author(s):  
Pradeep Kumar Mishra ◽  
Yogendra K. Gautam ◽  
J.N. Prasad ◽  
A.K. Choudhary ◽  
Ramesh Chandra
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Soda Lime ◽  
Optical Transmittance ◽  
Soda Lime Glass ◽  
Processing Parameter ◽  
Electrical And Optical Properties ◽  
Working Pressure ◽  
Soda Lime Glass Substrate ◽  
Ar Gas

CuIn0.8Ga0.2Se2 (CIGS) thin films have been successfully deposited on soda lime glass substrate at different working (Ar gas) pressures by Pulsed laser deposition (PLD). The effect of working pressure on the structural, electrical and optical properties of CIGS thin films has been investigated. All deposited CIGS thin films are found to be polycrystalline in nature with preferred orientation along (112). Crystallinity of CIGS thin films has been improved with decreasing of working pressures in PLD chamber. Stoichiometry of CIGS thin films has been maintained for all working pressures. Optical transmittance and electrical sheet resistance of CIGS thin films have been found to decrease with decrease of working pressure. The results of the present study signify that desired structural, electrical and optical properties of CIGS thin films can be obtained by changing the processing parameter in PLD method.Keywords: CIGS, XRD, Stoichiometry, UV-Vis-NIR spectrophotometer.

scholarly journals Influence of Molybdenum Back Contact on the PID Effect for Cu(In,Ga)Se2 Solar Cells

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 794 ◽  
Author(s):  
Oliver Salomon ◽  
Wolfram Hempel ◽  
Oliver Kiowski ◽  
Erwin Lotter ◽  
Wolfram Witte ◽  
...  
Keyword(s):  
Solar Cells ◽  
Glass Substrate ◽  
Optical Emission ◽  
Soda Lime ◽  
Deposition Process ◽  
Window Layer ◽  
Soda Lime Glass ◽  
Back Contact ◽  
Doping Density ◽  
Soda Lime Glass Substrate

The authors investigated the effect of an applied high voltage (1 kV) across the thickness of a soda-lime glass substrate of Cu(In,Ga)Se2 (CIGS) thin-film solar cells. Two types of CIGS cells were tested, differing only in the deposition process of the molybdenum (Mo) back contact. Whilst one cell type was susceptible to potential induced degradation (PID), the other exhibited highly increased stability against PID. PID occurs for PID-susceptible cells after the transfer of a certain amount of charge through the soda-lime glass substrate when the Mo back contact of the cell operates as a cathode (negatively biased versus backside of the substrate). Capacitance–voltage and electron-beam-induced current measurements showed an enlarged space charge region expanding to the Mo back contact and a lowered doping density by a negative potential for PID-susceptible cells. Glow discharge optical emission spectroscopy (GDOES) revealed an accumulation of sodium (Na) in the solution-grown CdS buffer layer and a segregation on the surface of the ZnO:Al window layer for higher charges for PID-susceptible cells. Cells with increased PID immunity did not show an increase of Na for charges up to around 9 mC/cm². We demonstrate that it is possible to improve the PID stability of CIGS solar cells by modification of the molybdenum back contact.

Influence of proton irradiation and development of flexible CdTe solar cells on polyimide

2001 ◽  
Vol 668 ◽  
Author(s):  
A. Romeo ◽  
D.L. Bätzner ◽  
H. Zogg ◽  
A.N. Tiwari
Keyword(s):  
Solar Cells ◽  
Proton Irradiation ◽  
Soda Lime ◽  
High Energy ◽  
Soda Lime Glass ◽  
Vacuum Deposition ◽  
Soda Lime Glass Substrate ◽  
Polymer Substrates ◽  
Cdte Solar Cells ◽  
Vacuum Deposition Method

ABSTRACTCdTe/CdS solar cells of ∼10% efficiency, developed with a vacuum deposition method were irradiated with high-energy protons of different fluences. The Voc and f.f. of irradiated cells increase or decrease depending on the fluence. The normal soda lime glass substrate darkens under the irradiation; therefore low Isc is measured. Measurements suggest that CdTe solar cells are highly stable under proton flux. Flexible and lightweight solar cells were developed in a superstrate configuration on polymer substrates. 8.6 % efficiency cells with Voc∼770 mV and Isc of 20.3 mA/cm2 were achieved.

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.

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