VERSIUNEA IN LIMBA ROMANA
Project: 288/2014
Title: Multilayered Photovoltaic Structures for Space Applications
Public Budget: 1.500.000 lei
Own Budget: 187.500,00 lei
Duration: 24 months
Funding Agency:
Executive Agency for Higher Education, Research, Development and Innovation (UEFISCDI), http://uefiscdi.gov.ro/
Project Coordinator: University of Bucharest
Partnership:
- National R&D Institute for Materials Physics
- National R&D Institute for Nuclear Physics and Engineering “Horia Hulubei”
- SC MGM STAR Construct SRL
Project director: Prof.univ.dr. Stefan ANTOHE
Contact: santohe@solid.fizica.unibuc.ro
Summary:
Thin film based PV structures are well fitted for space technology, due to their reduced mass. This proposal aims at investigating technological routes for fabricating thin film based multiple junction photovoltaic (PV) structures of the type ZnS/ZnSe/CdTe in superstrate configurations and to study their endurance to energetic (2-10 MeV) protons and alpha particles, which are the main components of cosmic rays, at 1010 - 1014 cm-2 fluencies. In the superstrate configuration one starts with depositing the transparent front-electrode onto the glass substrate which supports the entire structure, and then, on top of it the ZnS, ZnSe, CdTe layers and finally the back-electrode. The efficiencies of the cells in superstrate configurations will be characterized, and also their endurance to irradiation. Special attention will be paid to the physical properties and the electrical response of the back-contact metal/CdTe. CdTe, an excellent photon absorber with a forbidden gap of 1.4 eV and a large light absorption coefficient, is known as a “difficult” semiconductor: due to its rather large work function, a special care must be taken to prepare a quasi-ohmic low-resistance contact with a metal. Ion implantation will be used to control electrical properties of CdTe layer, by doping with properly selected electrically active impurities. A special attention will be paid to the quality of interfaces; an optimization of the PV structures will be performed. The nature of the defects introduced by irradiation will be studied and their influence on the performance of the structures will be indicated.
WP 1 / 2014 - Preparation and characterization of ZnSe/CdTe heterostructures
Objectives:
- To optimize ZnSe/CdTe interface
- To fabricate and characterize ZnSe/CdTe heterostructures in superstrate configuration
Tasks:
1.1 Deposition of component thin films and optimization of ZnSe/CdTe interface
1.2 Fabrication of ZnSe/CdTe heterostructures
1.3 Fabrication of photovoltaic structures in superstrate configuration, based on ZnSe/CdTe heterostructure (1st part)
A systematic study upon the influence of growth parameters on the physical properties of ZnSe and CdTe films was performed. The growth conditions, resulting in an optimised photovoltaic response of
ITO/ZnSe/CdTe/Me photovoltaic structures, were determined. The formation of stable quasi-ohmic back contacts CdTe/Me was one of the main tasks addressed at this stage.
Publicaţii:
- O. Toma, S. Antohe, Chalcogen. Lett. 11, 611 (2014)
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