Das Projekt "Substrat- und Sperrschichtoptimierung fuer im CVD-Verfahren hergestellte Duennschicht-Siliziumkristall-Solarzellen" wird vom Umweltbundesamt gefördert und von Fraunhofer-Institut für Solare Energiesysteme durchgeführt. Objective: A consortium has been formed by partners stemming from research and industry in order to make a further step towards the development of a cost-effective thin-film crystalline Si solar cell technology, based on thermally assisted Chemical Vapour Deposition (CVD) as deposition technique. This project should result in a thin-film crystalline Si low-cost PV module with a competitive cost/Wp. Description of work: The numerous possible options for thin-film crystalline Si solar cells (for substrate and barrier layer) and the absence of real progress on the level of equipment development for large-volume Si-layer deposition bear an inherent risk for subcritical research in this area. The consortium defined a clear strategy as far as substrates and deposition system are concerned. - Concerning the substrates, the number of options has been reduced to 3 options (Si-ribbons, a conductive ceramic: Si-infiltrated SiAlON and an insulating ceramic: SiAlON). - Together with the development and optimisation of the barrier layers, 4 technically relevant substrate/barrier layers schemes are investigated on cell level: Si-ribbons with and without barrier layer, Si-infiltrated SiAlON-substrates with a conductive SiC-layer, SiAlON-substrates and Si-ribbons with an insulating oxide barrier layer. After the Midterm Assessment, the number of substrate/barrier schemes is reduced to 2 (a conductive and non-conductive scheme), based on the results of a laboratory-type comparison of cells and the first cost projections. - Concerning the development of a high-throughput CVD-system, first steps toward a continuous Si-deposition system are taken. The consortium wishes to assess and reduce the running costs of such system. Specifically the costs associated with waste treatment and a reduction of the gas consumption through a H2-recirculation system will be looked at in more detail . In the first phase of the project these aspects will be studied. After the Midterm Assessment this deposition system will be intensively used for the growth of the Si-layers on the selected substrates, which will be processed into solar cells using processes, compatible with the industrial reality. Expected Results and Exploitation Plans: - The selection of a suitable low-cost substrate, compatible with Si-deposition by means of thermally-assisted Chemical Vapour Deposition (and possibly a liquid phase recrystallisation step); - The development of suitable barrier layers to prevent impurity indiffusion from the low-cost substrate into the active layer and to optimise internal reflection; - The assessment of a continuous high-throughput CVD-reactor, compatible with the requirements of the solar cell industry; - A module of 30x30 cm2 on the selected conductive substrate/barrier layer combination with an efficiency = 12 per cent obtained by a two-side contacting technology. Prime Contractor: Interuniversity microelectronics centre, microsyst4ems, components and packaging advanced solar cells