scholarly journals Analysis of the properties of molybdenum and sodium-doped molybdenum thin films for back contact of CIGS solar cells

2020 ◽  
Author(s):  
C. Wongwanitwatta ◽  
M. Horprathum ◽  
C. Chananonnawathorn
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Back Contact ◽  
Cigs Solar Cells

scholarly journals In SituandEx SituStudies of Molybdenum Thin Films Deposited by rf and dc Magnetron Sputtering as a Back Contact for CIGS Solar Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
K. Aryal ◽  
H. Khatri ◽  
R. W. Collins ◽  
S. Marsillac
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Magnetron Sputtering ◽  
Layer Thickness ◽  
Compressive Strain ◽  
Back Contact ◽  
Dc Magnetron Sputtering ◽  
Bulk Layer ◽  
Cigs Solar Cells ◽  
Deposited Films

Molybdenum thin films were deposited by rf and dc magnetron sputtering and their properties analyzed with regards to their potential application as a back contact for CIGS solar cells. It is shown that both types of films tend to transition from tensile to compressive strain when the deposition pressure increases, while the conductivity and the grain size decreas. The nucleation of the films characterized byin situand real time spectroscopic ellipsometry shows that both films follow a Volmer-Weber growth, with a higher surface roughness and lower deposition rate for the rf deposited films. The electronic relaxation time was then extracted as a function of bulk layer thickness for rf and dc films by fitting each dielectric function to a Drude free-electron model combined with a broad Lorentz oscillator. The values were fitted to a conical growth mode and demonstrated that the rf-deposited films have already smaller grains than the dc films when the bulk layer thickness is 30 nm.

scholarly journals Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chuan Lung Chuang ◽  
Ming Wei Chang ◽  
Nien Po Chen ◽  
Chung Chiang Pan ◽  
Chung Ping Liu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Solar Cells ◽  
Indium Tin Oxide ◽  
Copper Indium Gallium Diselenide ◽  
Glass Substrates ◽  
Ito Film ◽  
Ito Thin Films ◽  
Cigs Solar Cells ◽  
Ito Films

Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were-1.6E+20 cm−3,2.7E+01 cm2/Vs,1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.

Above 15% Efficient Directly Sputtered CIGS Solar Cells Enabled by a Modified Back-Contact Interface

2021 ◽  
Author(s):  
Wanlei Dai ◽  
Zeran Gao ◽  
Jianjun Li ◽  
Shumin Qin ◽  
Ruobing Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Back Contact ◽  
Contact Interface ◽  
Cigs Solar Cells

Epitaxial Cu(In,Ga)Se 2 Thin Films on Mo Back Contact for Solar Cells

2019 ◽  
Vol 216 (16) ◽  
pp. 1900164 ◽  
Author(s):  
Yuta Ando ◽  
Ishwor Khatri ◽  
Hironori Matsumori ◽  
Mutsumi Sugiyama ◽  
Tokio Nakada
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Back Contact

scholarly journals Properties of Arsenic–Doped ZnTe Thin Films as a Back Contact for CdTe Solar Cells

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3706 ◽  
Author(s):  
Ochai Oklobia ◽  
Giray Kartopu ◽  
Stuart J. C. Irvine
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Open Circuit ◽  
Activation Process ◽  
Back Contact ◽  
Contact Activation ◽  
Doping Density ◽  
Cdte Solar Cells ◽  
Absorber Doping ◽  
P Type

As-doped polycrystalline ZnTe layers grown by metalorganic chemical vapor deposition (MOCVD) have been investigated as a back contact for CdTe solar cells. While undoped ZnTe films were essentially insulating, the doped layers showed significant rise in conductivity with increasing As concentration. High p-type carrier densities up 4.5 × 1018 cm−3 was measured by the Hall-effect in heavily doped ZnTe:As films, displaying electrical properties comparable to epitaxial ZnTe single crystalline thin films in the literature. Device incorporation with as-deposited ZnTe:As yielded lower photovoltaic (PV) performance compared to reference devices, due to losses in the open-circuit potential (VOC) and fill factor (FF) related to reducing p-type doping density (NA) in the absorber layer. Some minor recovery observed in absorber doping following a Cl-free post–ZnTe:As deposition anneal in hydrogen at 420 °C contributed to a slight improvement in VOC and NA, highlighting the significance of back contact activation. A mild CdCl2 activation process on the ZnTe:As back contact layer via a sacrificial CdS cap layer has been assessed to suppress Zn losses, which occur in the case of standard CdCl2 anneal treatments (CHT) via formation of volatile ZnCl2. The CdS sacrificial cap was effective in minimising the Zn loss. Compared to untreated and non-capped, mild CHT processed ZnTe:As back contacted devices, mild CHT with a CdS barrier showed the highest recovery in absorber doping and an ~10 mV gain in VOC, with the best cell efficiency approaching the baseline devices.

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.

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