[1] IMEC, Silicon Photovolta Grp, Kapeldreef 75, B-3001 Heverlee, Belgium
[2] Tech Univ Denmark, Natl Lab Sustainable Energy, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
[3] Univ Nacl Autonoma Mexico, Inst Energias Renovables, Temixco 62580, Morelos, Mexico
[4] Star Sci, 8730 Water Rd, Cotati, CA 94931 USA
[5] CNRS ICMCB, 87 Av Dr Schweitzer, F-33608 Pessac, France
[6] Sol Ideas Technol Dev, POB 5729, San Jose, CA 95150 USA
[7] Indian Inst Technol, Dept Phys, Chennai 600036, Tamil Nadu, India