Electrical and optical characterization of CdxZn1-xS and PbS thin films for photovoltaic applications PDF Download
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Author: Cliff Orori Mosiori
Publisher: GRIN Verlag
ISBN: 3656718407
Category : Science
Languages : en
Pages : 118
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Book Description
Master's Thesis from the year 2011 in the subject Physics - Applied physics, grade: A, Kenyatta University, course: Master of Science ( Physics), language: English, abstract: In this research an n-type CdxZn1-xS and p-type PbS thin films were optimised for solar cell applications employing chemical bath deposition technique. The thin films were prepared using thiourea and nitrates of cadmium, zinc and lead. Deposition of optimised CdxZn1-xS was done by CBD at 820 C and in alkaline conditions while that of PbS was done at room temperature and both films at normal atmospheric pressure utilizing aqueous conditions. This study concentrated on optimising optical and electrical characterization of the films. Optical constant suitable for photovoltaic applications were sort for and for this purpose a UV VIS IR spectrophotometer 3700 DUV was utilised while the electrical properties were investigated using a four point probe connected to a Keithley 2400 source meter interfaced with computer. The optical band gap of the as deposited CdxZn1-xS films varied from 2.47eV (x =0.6) to 2.72 eV (x =1.0), and transmittance above 79% in the VIS - NIR region for the concentration range of x = 0.6 to 1.0, that is, the band gap increased with increasing Zn concentration of the alloy and Cd06Zn0.4S sample showed the widest band gap. It was obtained that the presence of zinc increased optical band gap. The average extinction coefficients for the as deposited CdxZn1-xS samples were very low revealing that they absorb very little radiation hence a good window layer material. As measured by the four point probe connected to a Keithley 2400 source meter, electrical resistivity increased with increase in Zn in the bath in CdxZn1-xS and a resistivity range of 9.5×101 – 1.22× 102 Ω-cm was obtained. These properties are appropriate for window layers used for photovoltaic cell applications. PbS thin films had a band gap of 0.89 eV and a transmittance of below 55% appropriate for absorber layers of photovoltaic cells and a resistivity range of 6.78 × 103 to 1.26 × 104 Ω-cm. The fabricated photovoltaic cell had a short circuit current, Isc = 0.031 A, open voltage, Voc = 0.37V, efficiency, η = 0.9% and a fill factor, FF = 0.66 implying that the two materials are appropriate for photovoltaic applications especially in the VIS and IR light spectrum.
Author: Cliff Orori Mosiori
Publisher: GRIN Verlag
ISBN: 3656718407
Category : Science
Languages : en
Pages : 118
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Book Description
Master's Thesis from the year 2011 in the subject Physics - Applied physics, grade: A, Kenyatta University, course: Master of Science ( Physics), language: English, abstract: In this research an n-type CdxZn1-xS and p-type PbS thin films were optimised for solar cell applications employing chemical bath deposition technique. The thin films were prepared using thiourea and nitrates of cadmium, zinc and lead. Deposition of optimised CdxZn1-xS was done by CBD at 820 C and in alkaline conditions while that of PbS was done at room temperature and both films at normal atmospheric pressure utilizing aqueous conditions. This study concentrated on optimising optical and electrical characterization of the films. Optical constant suitable for photovoltaic applications were sort for and for this purpose a UV VIS IR spectrophotometer 3700 DUV was utilised while the electrical properties were investigated using a four point probe connected to a Keithley 2400 source meter interfaced with computer. The optical band gap of the as deposited CdxZn1-xS films varied from 2.47eV (x =0.6) to 2.72 eV (x =1.0), and transmittance above 79% in the VIS - NIR region for the concentration range of x = 0.6 to 1.0, that is, the band gap increased with increasing Zn concentration of the alloy and Cd06Zn0.4S sample showed the widest band gap. It was obtained that the presence of zinc increased optical band gap. The average extinction coefficients for the as deposited CdxZn1-xS samples were very low revealing that they absorb very little radiation hence a good window layer material. As measured by the four point probe connected to a Keithley 2400 source meter, electrical resistivity increased with increase in Zn in the bath in CdxZn1-xS and a resistivity range of 9.5×101 – 1.22× 102 Ω-cm was obtained. These properties are appropriate for window layers used for photovoltaic cell applications. PbS thin films had a band gap of 0.89 eV and a transmittance of below 55% appropriate for absorber layers of photovoltaic cells and a resistivity range of 6.78 × 103 to 1.26 × 104 Ω-cm. The fabricated photovoltaic cell had a short circuit current, Isc = 0.031 A, open voltage, Voc = 0.37V, efficiency, η = 0.9% and a fill factor, FF = 0.66 implying that the two materials are appropriate for photovoltaic applications especially in the VIS and IR light spectrum.
Author: Cliff Orori Mosiori
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659414039
Category :
Languages : en
Pages : 120
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Book Description
A study of CdZnS and PbS nano-crystalline thin films deposited by chemical bath deposition (CBD) method has been made using Four point probe for electrical sheet resistivity, UV-Vis spectroscopy and solar simulator for optical and Photovoltaic cell properties respectively. Sheet resistivity for CdZnS thin films was found to decrease as the concentration of Zn increased while PbS thin films had their sheet resistivity increase with increase in bath concentrations. Optical band gap for CdZnS had a tunability depending on the various Zn2+ concentrations used successfully as demonstrated by UV-VIS-NIR spectroscopy. Transmittance in CdxZn1-xS was found to be above 80%, optical band gap of 2.47 - 2.72 eV, refractive index of 2.58 - 2.39, and sheet resistivity of 1.09 - 1.36 x 102 -cm for x = 1.0 - 0.6. The thin films were suitable for use as window films for optical devices. PbS films were good absorbers with a band gap of 0.88 eV and transmittance below 55%, Electrical resistivity varying from 6.78 x 103 to 1.26 x 104 -cm, conductivity of 1.09 x 10-4 to 7.9 x 10-5 S-cm-1. The PbS films were suitable as absorber films for photovoltaic cell applications.
Author: Cliff Orori Mosiori
Publisher: diplom.de
ISBN: 3954898462
Category : Technology & Engineering
Languages : en
Pages : 220
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Book Description
Thin films can be used to fabricate optoelectronic devices. Technology is currently focusing on ternary thin film composition because of their structure, inter-band transitions and other optical properties that can be maximized. This book discusses in detail the optical characteristics of ternary thin films and further investigates the behavior of Iron Zinc Sulphide, Lead Silver Sulphide, Copper Silver Sulphide, Copper Zinc Sulphide and Cadmium Zinc Sulphide. Thin films are of fundamental importance in modern technology.
Author:
Publisher:
ISBN:
Category :
Languages : ko
Pages :
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Author: Cliff Orori Mosiori
Publisher: Anchor Academic Publishing
ISBN: 3954894327
Category : Science
Languages : en
Pages : 393
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Book Description
Solid state physics is a fascinating sub-genre of condensed matter physics - though some graduate students consider it a very boring and tedious subject area in Physics and others even call it a “squalid state”. Topics covered in this book are built on standard solid state physics references available in most online libraries or in other books on solid state physics. The complexity of high speed semiconductor physics and related devices arose from condensed solid state matter. The content covered in this book gives a deep coverage on some topics or sections that may be covered only superficially in other literature. Therefore, these topics are likely to differ a great deal from what is deemed important elsewhere in other books or available literature. There are many extremely good books on solid-state physics and condensed matter physics but very few of these books are restricted to high speed semiconductor physic though. Chapter one covers the general semiconductor qualities that make high speed semiconductor devices effect and includes the theory of crystals, diffusion and ist mechanisms, while chapter two covers solid state materials, material processing for high speed semiconductor devices and an introduction to quantum theory for materials in relation to density of states of the radiation for a black body and ist radiation properties. Chapter three discuss high speed semiconductor energy band theory, energy bands in general solid semiconductor materials, the Debye model, the Einstein model the Debye model and semiconductor transport carriers in 3D semiconductors while chapter four discuss effect of external force on current flow based on the concept of holes valence band, and lattice scattering in high speed devices. Chapter five briefly describes solid state thermoelectric fundamentals, thermoelectric material and thermoelectric theory of solids in lattice and phonons while chapter six scattering in high field effect in semiconductors in inter-valley electron scattering and the associated Fermi Dirac statistics and Maxwell-Boltzmann approximation on their carrier concentration variation with energy in extrinsic doping chapter seven covers p-n junction diodes, varactor diode, pin diode Schottky diode and their transient response of diode in multi-valley semiconductors. Chapter eight discusses high speed metal semiconductor field effect transistors.
Author: Mohammad Reza Behfrooz
Publisher:
ISBN:
Category :
Languages : en
Pages : 65
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Author: Dipendra Adhikari
Publisher:
ISBN:
Category : Thin films
Languages : en
Pages : 150
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Author: Spencer Lewis Buckner
Publisher:
ISBN:
Category : Solar cells
Languages : en
Pages : 244
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Author: Okechukwu Anthony Ogbuu
Publisher:
ISBN: 9781369128499
Category :
Languages : en
Pages : 104
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To favorably compete with fossil-fuel technology, the greatest challenge for thin film solar-cells is to improve efficiency and reduce material cost. Thickness scaling to thin film reduces material cost but affects the light absorption in the cells; therefore a concept that traps incident photons and increases its optical path length is needed to boost absorption in thin film solar cells. One approach is the integration of low symmetric gratings (LSG), using high index material, on either the front-side or backside of 30 um thin c-Si cells. In this study, Multicomponent TeO2–Bi2O 3–ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy. The results indicate that TBZ glass thin film is a suitable material for front side LSG material photovoltaic and photonics applications due to their amorphous nature, high refractive index (n > 2), broad band optical transparency window, low processing temperature. We developed a simple maskless method to pattern sputtered tellurite based glass thin films using unconventional agarose hydrogel mediated wet etching. Conventional wet etching process, while claiming low cost and high throughput, suffers from reproducibility and pattern fidelity issues due to the isotropic nature of wet chemical etching when applied to glasses and polymers. This method overcomes these challenges by using an agarose hydrogel stamp to mediate a conformal etching process. In our maskless method, agarose hydrogel stamps are patterned following a standard soft lithography and replica molding process from micropatterned masters and soaked in a chemical etchant. The micro-scale features on the stamp are subsequently transferred into glass and polymer thin films via conformal wet etching. High refractive index chalcogenide glass (n = 2.6) thin films with composition As20Se80 was selected for backside LSG material due to their attractive properties. We developed an optimized integration protocol for LSG integration and successfully integrated these LSG structures at the back side of both 30 μm c-Si solar cells and standalone 30 μm c-Si wafers. Optical and electrical characterization of LSG on thin c-Si cells shows that LSG structures create higher absorption enhancement and external quantum efficiency at long wavelengths.
Author: Cesar Antonio Estrada-Mendizabal
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
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