Photovoltaic Power Generation

Amorphous silicon PV panel mass production will require to mas­ ter plasma chemical deposition in terms of large sizes, cost, maintenance and all other problems related to industrialization. Since plasma deposition is a novel technique, the development of all this production related know how involves a considerable technical research effort. The major problems related to the design of a production deposi­ tion machine are the following - deposition should be uniform on very large area substrate (typical dimension 1 meter) ; - the deposited amorphous silicon should have good electronic properties (density of state of the order or less than 16 3 10 cm /eV) and very low impurities concentrations (for exam­ ple oxygen atomic concentration should idealy be less than 0. 01 %) ; - the film stress should be limited, the density of ponctual defects (particulates) should remain reasonable (less than 2 per 100 cm ) ; - dopant level control should be stable and efficient ; - silane consumption should remain reasonably efficient - financial cost being important the machine productivity should be high hence deposition rate optimized ; - downtime due to maintenance should be reduced to a minimum. We present here some results on the R&D effort addressed to the above mentioned problems. An original single chamber was designed. This machine will be made available on the market for R&D purposes by a process machine company. Finally the maintenance problem is considered. Plasma cleaning based on a fluorine containing etchant gases is studied and evaluated. 2.

Amorphous Silicon Solar Cells (AMOR).- 1. A-Si Solar cells prepared by the glow discharge technique.- · Development of the scientific and technical basis for integrated amorphous silicon modules.- -Deposition techniques for a-Si.- -Physics of the pin device.- -Improvement of the device structure.- -Description of the research work carried out at SCK/CEN.- -AES analysis of the SnO2/a-Si:H inferface.- -The French contribution to the project.- -Light trapping in a-Si:H solar cells by texturization of the glass substrate.- -Photochemical process induced by a low pressure Hg lamp and a pulsed ArF excimer laser for depositing hydrogenated silicon films.- -Vacuum UV photo CVD for amorphous silicon carbon alloys.- -Preparation of improved amorphous silicon cells with p-i-n structure based on new volatile hydrides and fluorides of silicon and germanium.- -Development of the scientific and technical basis for integrated amorphous silicon modules.- · Low-gap alloys for amorphous silicon based solar cells -Narrow band-gap alloys for the improvement of efficiency of amorphous silicon-based solar cells.- -The Italian contribution to the project.- -Characterization of amorphous silicon alloys through thermal H effusion.- -Characterization of hydrogenated amorphous silicon by photo deflection spectroscopy.- • Kinetic study of the deposition process of glow discharge a-Si:H for high efficiency solar cells.- -The Greek contribution to the project.- -Characterization of SiH4:H2 plasmas for a-Si:H film deposition.- · Electro-Optical properties of a-Si;H/?C-Si;H and a-Si:C:H/?C-Si:C:H undoped and doped films produced by a TCDDC system.- · Eyaluation of promising alternative a-Si deposition method.- · Development of a high deposition rate technique for device quality thin films of hydrogenated amorphous silicon.- · Preparation of solar grade amorphous silicon for PV cells by means of an electrolytic process.- · Hydrogenated amorphous silicon by disilane LPCVD.- Thin Film Solar Cells From Alternative Materials (ALTERNA).- 1. High efficiency crystalline silicon thin-film solar cells.- · High efficiency thin-film solar cells on upgraded metallurgical grade silicon substrates.- · The French contribution to the project.- · Modelling of epitaxial cells on UMG silicon and feasibility of a high throughput epitaxial reactor.- · Growth and characterization of poly-Si ingots.- · Growth and characterization of poly-Si ingots.- 2. Thin film solar cells based on II-VI and ternary chalcopyrite semiconductor materials.- · Thin film solar cells based on the chalcopyrite semiconductor  U(GA,IN)SE.- · Research and development on sprayed CdS-CuInSe2 thin filmsolar cells.- · CuInSe2/CdS thin film solar cells by R.F. sputtering.- · Electrochemical study of chalcopyrite semiconductor s.- · Thin film of copper indium diselenide for PV devices.- · Development of CdSe thin film solar cells with regard to the requirements for the use in tandem structures.- · The fabrication of merocyanine dyes for use as PV materials.- 3. III-V compound semiconductors for use in thin film cells or in monolytic multilayer cells.- · Optimization of high efficiency multilayer solar cells based on III-V compounds.- -MOCVD and characterization.- -KBE and physical analysis.- -Inhomogeneities in LEC GaAs substrates for solar cell applications.- · High efficiency multispectral cells based on III-V compound semiconductors.- GaAs thin film solar cells obtained by vapour phase homoepitaxy (VPE) on reusable substrates.- -The contribution by ENEA.- -The contribution by CISE.- · Study on the applicability of the ionized cluster beam deposition technology for GaAs thin film solar cells.- High efficiency III-V solar cells for use with fluorescent concentrators.- -The German contribution to the project.- -The Belgian contribution to the project.- · Hydrogen effect on the electrical properties of amorphous gallium arsenide.- List of authors.