1,721,101 research outputs found
CdTe-Based Photodetectors and Solar Cells
No full textIn this chapter we will show how much appreciated were the electro-optical characteristics of one of the most widely used semiconductors of the II-VI family, Cadmium Telluride or CdTe. High quality single crystals with industrially appreciable dimensions have been easily obtained since the beginning of the CdTe epopee. Exploiting its very high transparency in the mid-infrared it was firstly employed as window for i.r. laser applications. Its role, as a material for developing electro-optical modulators needed for the evolution of power CO2-based lasers, was crucial. In more modern times, with the advent of nanotechnologies, CdTe has found considerable success as a UV-Vis photodetector if used in the form of dots, ribbons, belts and, more in general, when it is possible to exploit quantum confinement in reduced dimensions. But where CdTe has been most successful is in the photovoltaic field, where solar cells and photovoltaic modules, with conversion efficiency greater than 22% and 19% respectively, have been made. To date, among thin-film technologies, CdTe-based modules occupy the first place on the market and more than 8% globally.
We will talk about this and much more in the rest of this chapter by going into the detail of the photodetectors and, mainly, of the solar cells, revealing the smartest tricks normally used to make these devices sustainable, efficient and cost-effective
“The role of CdS preparation method in the performance of CdTe/CdS thin film solar cell”
No full textA study of CdS films and how they can influence the CdS/CdTe solar cell interface is reported. CdS is prepared by two different methods. The first one is the closed-space-sublimation (CSS) and the second one is sputtering. Both methods, if they are used properly, are suitable to prepare cells with efficiencies larger than 14%. We found out that, in order to obtain high efficiency cells, CdS prepared by CSS has to be made in presence of O/sub 2/, while CdS prepared by sputtering has to be made in presence of fluorine. In both cases the films need to be washed in acetic acid or annealed at 400-420/spl deg/C in an atmosphere containing H/sub 2/. Both treatments seem to be effective in removing an insulating surface layer, which is formed during the CdS preparation. This insulating material could behave as a good passivant for the CdS grain boundaries
Key Developments In CuInGaSe2 Thin Film Solar Cell
No full textNowadays, thin-film solar cells potentially offer a suitable technology for solving the energy production problem with an environmentally friendly method. Besides, thin film technologies show advantages over their bulk-semiconductor counterparts due to their lighter weight, flexible shape and device fabrication schemes and low cost in large-scale industrial production. Although many books currently exist on general concepts of PV materials and devices, few are offering a comprehensive overview of the fast development in thin film Cu(In,Ga)Se2-based solar cells. “Key Developments in CuInGaSe2 Thin Film Solar Cells” would provide an international perspective on the latest research on this topic. It presents a wide range of scientific and technological aspects on basic properties and device physics of high-efficiency CIGS solar cells from the last research frontier point of view.
The book was designed for photovoltaic researchers and scientists, students and engineers, with the mission to provide knowledge of the mechanisms, materials, devices, and applications of CIGS-based technology necessary to develop cheaper and cleaner renewable energy in the coming years
An innovative process suitable to produce high-efficiency CdTe/CdS thin-film modules
No full textA novel process, different in all steps from the common process usually used to fabricate CdTe/CdS thin-film solar cells, is described. This process on the one hand permits one to obtain high-quality layers and high-quality cells and on the other hand is particularly suitable to be scaled up at an industrial level. In fact, neither etching baths nor CdCl(2) deposition is used in this process. The back contact is made with a buffer layer capable of stabilizing Cu and, as a consequence, the devices are very stable. (C) 2009 Elsevier B.V. All rights reserved
A PROCESs FOR LARGE-SCALE PRODUCTION OF CDTE/CDS THNI FLIM SOLAR CELLS
No full textA process for the large-scale production of CdTe/CdS thin film solar cells, said films being deposited as a sequence on a transparent substrate, comprising the steps 5 of: depositing a film of a transparent conductive oxide (TCO) on said substrate; depositing a film of CdS on said TCO film; depositing a film of CdTe on said CdS film; treating said CdTe film with CdCl2; depositing a back-contact film on said treated CdTe film. The treatment 10 of the CdTe film with CdCl2 comprises the following steps: forming a layer of CdCl2 on the CdTe film by evaporation, while keeping the substrate at room temperature; annealing said CdCl2 layer in a vacuum chamber at 380-420°C and 300-1000 mbar under inert gas atmosphere; removing the inert gas from said chamber to produce vacuum condition, while the substrate is kept to a temperature of 350-420°C whereby any residual CdCl2 is evaporated from the CdTe film surface
Processo per la Produzione di Celle Solari a Film Sottili
No full textLa presente invenzione si riferisce ad un processo migliorato per la produzione di celle solari a film sottili in cui lo strato assorbitore è costituito da CuInGaSe2, che consente di preparare uno strato assorbitore omogeneo, di stechiometria uniforme anche su ampie aree, in condizioni di maggiore sicurezza, velocità e semplicità, che rendono più efficiente ed economico il processo complessivo di produzione
CuInSe2/CdS thin film solar cells by r.f. sputtering
No full textCuInSe2/CdS thin film solar cells were prepared by rf sputtering on an Al-covered glass substrate. The Al layer, deposited using an electron gun, is crystalline with an average grain size of 100μ. The Mo bottom contact, the CuInSe2 and CdS films were sputtered in sequence in the same sputtering chamber without breaking the vacuum. The CdS film deposited at substrate temperature of 200°C has a resistivity of ≈1 Ωcm due to small amount of H added during the deposition which increases the S vacancies in the film. CuInSe2/CdS sputtered solar cells have an efficiency of ≈4-5%. A higher efficiency can be obtained by improving the structural and electro-optical properties of CuInSe2 thin films
METHOD FOR THE FORMATION OF A NON-RECTIFYING BACK-CONTACT IN A CDTE/CDS THIN FILM SOLAR CELL
No full textA method of forming a non-rectifying, ohmic contact on a p-type semiconductor CdTe thin film, which comprises the steps of depositing a layer of As2Te3 on a CdTe layer at a substrate temperature generally within a range of ambient temperature and 200° C.; depositing a layer of Cu on the As2Te3 layer; and bringing at least the deposited Cu layer to a temperature generally within a range of 150° C. and 250° C. The method is used to form a stable contact on CdTe/CdS thin film solar
Large Crystalline Grain CdTe Thin Films for Photovoltaic Application
No full textA simple new method suitable to grow large crystalline grain CdTe thin films on glass substrates has been developed. CdTe films which exhibit a grain size larger than 20 μm have been obtained. The films are p-type with a resistivity of about 100 Ωcm. Backwall CdTe/CdS thin film solar cells with an efficiency above 9% have been prepared
- …
