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HL: Halbleiterphysik

HL 30: Photovoltaik

HL 30.14: Vortrag

Mittwoch, 26. März 2003, 17:45–18:00, BEY/81

Amorphous/Crystalline Heterojunction Solar Cells — •A. Froitzheim¹, M. Scherff², A. Ulyashin², M. Schmidt¹, W. Fahrner², and W. Fuhs¹ — ¹Hahn-Meitner-Institut Berlin — ²Fernuniversitaet Hagen

The use of amorphous (a-Si:H) as an ultrathin emitter in an amorphous/crystalline heterostructure is an interesting candidate for a high efficiency, low temperature processed solar cell. Simple Transparent Conductive Oxide (TCO)/a-Si:H(n)/c-Si(p) solar cell heterostructures with varied emitter structures have been prepared and a confirmed efficiency of 16.2 have been reached. This is to our knowledge the highest efficiency for an a-Si:H(n)/c-Si(p) structure. A minimum thickness of about 5 nm is necessary in order to prevent the solar cell characteristics from a negative influence of the front contact, which manly reduces the open circuit voltage. The samples are investigated by current-voltage measurements and internal quantum efficiency in order to determine loss mechanisms. Photoluminescence measurements on structures with an intrinsic a-Si:H buffer layer a-Si:H(n)/a-Si:H(i)/c-Si(p) indicate a better passivation of the a-Si:H/c-Si interface compared to a simple a-Si:H(n)/c-Si(p) structure without the buffer layer. This offers a way to further reduce interface recombination and thus to enhance open circuit voltage.