Title :
CIGS solar cells grown by a three-stage process with different evaporation rates
Author :
Chirila, A. ; Guettler, D. ; Brémaud, D. ; Buecheler, S. ; Verma, R. ; Seyrling, S. ; Nishiwaki, S. ; Haenni, S. ; Bilger, G. ; Tiwari, A.N.
Author_Institution :
Lab. for Thin Films & Photovoltaics, EMPA, Duebendorf, Switzerland
Abstract :
Solar cells based on polycrystalline Cu(In,Ga)Se2 (CIGS) absorber layers have shown high potential for low cost photovoltaic energy conversion. Our group has achieved 18.1% efficient cells on glass substrates and 14.1% on flexible polyimide foils without antireflection (AR) coating. These results were achieved by applying a three-stage evaporation process with common growth rates of about 35 nm/min. Aim of this study was to enhance the growth rates of layers deposited at low substrate temperature (450°C) suitable for polyimide foils and to investigate structural properties of CIGS layers and photovoltaic properties of solar cells. It was found that very high deposition rates of 500 nm/min during the 2nd and 3rd stage of the evaporation process are feasible, maintaining high absorber quality and performance of solar cells.
Keywords :
copper compounds; gallium compounds; indium compounds; photovoltaic effects; semiconductor growth; semiconductor thin films; solar cells; ternary semiconductors; thin film devices; vacuum deposited coatings; vacuum deposition; CuInGaSe2; flexible polyimide foils; low cost photovoltaic energy conversion; photovoltaic properties; polycrystalline absorber layers; solar cells; structural properties; temperature 450 degC; three-stage evaporation; Coatings; Costs; Glass; Grain size; Laboratories; Photovoltaic cells; Polyimides; Scanning electron microscopy; Substrates; Temperature;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2009 34th IEEE
Conference_Location :
Philadelphia, PA
Print_ISBN :
978-1-4244-2949-3
Electronic_ISBN :
0160-8371
DOI :
10.1109/PVSC.2009.5411161
