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MODELLING OF SOLAR CELLS ON UPM-SILICON AND FEASIBILITY STUDY OF A HIGH THROUGHPUT EPITAXIAL REACTOR

Objective

EPITAXIAL SOLAR CELLS ON LOW GRADE SUBSTRATES HAVE SHOWN EFFICIENCIES OVER 11 % AND PROMISES EFFICIENCIES OF AT LEAST 13 %. THE PRACTICAL INTEREST OF THE APPROACH IS BASED ON THE ACHIEVEMENT OF A HIGH THROUGHPUT REACTOR FOR THE CHEAP EPITAXY FORMATION, WITH THE POSSIBILITY OF GRADED PROFILES THAT WE CONSIDER IMPORTANT IN OUR APPROACH.

A SYNTHETIC MODELLING OF EPITAXIAL SOLAR CELLS ON UPGRADED METALURGICAL GRADE SEMICONDUCTOR HAS BEEN DEVELOPED.
IT IS CONCLUDED THAT THE QUALITY OF THE SUBSTRATE IS OF MINOR IMPORTANCE, AND SINGLE STEP OF RECRYSTALLIZATION, JUST ENOUGH FOR HAVING BIG GRAIN SIZE, IS RECOMMENDED FOR LOW COST.
WITH THIS MATERIAL THERE IS THE RISK THAT THE EPITAXI LIFETIME IS NOT LONG ENOUGH. IN THIS CASE THE USE OF GRADED EPITAXIES REMOVES THE SHORT LIFETIME DRAWBACKS PERMITTING TO EXPECT EFFICIENCIES UP TO 13%.
A NOVEL HIGH THROUGHOUT EPITAXIAL REACTOR HAS BEEN PROPOSED: THE SO-CALLED SKACKED SUSCEPTOR EPIREACTOR. THE REACTOR CAN OPERATE WITH CHLOROSILANES OR WITH EG SILICON AS SOURCE, AND MUST USE RECIRCULATION OR MIXED CONDITIONS.
UNDER THESE CONDITIONS THE COST IS ALMOST TOTALLY LIMITED BY THE RAW MATERIAL COSTS AND CAN GO BELOW $0.5 PER EPITAXY WITH CHLOROSILANES ARE USED, PROVIDED A MASS PRODUCTION OF THE RAW MATERIAL, OR BELOW THESE FIGURES IF THE SI SOURCE IS USED.
IN ALL CASES THE EPITAXIAL CELLS HAVE A POTENTIAL COST BELOW THE CELLS BASED ON UPGRADED MG SI WITHOUT EPITAXY, AND CAN MEET THE $2 PER WATT PEAK FORGET.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSIDAD POLITECNICA DE MADRID
Address
Av. Ramiro De Maeztu 7 S/n
28040 Madrid
Spain