Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 84: Poster: Electronic structure theory / Carbon (other than graphene) / Si, Ge, and SiC / III-V semiconductors (other than nitrides)

HL 84.8: Poster

Mittwoch, 2. April 2014, 17:00–20:00, P1

I-V characterisation of a-Si/c-Si heterojunctions — •Patrick Thoma, Evelyn T. Breyer, Ovidiu D. Gordan, and Dietrich R. T. Zahn — Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany

As pure crystalline silicon solar cells have limited light absorption efficiency due to their indirect band gap requiring thick absorption layers manufactured in an energy intensive production process, research tries to find new cheaper and more efficient systems for energy harvesting. One promising approach is the use of so called heterojunction solar cells, consisting of different semiconducting material layers which have advantages like complementary absorbance of light in various wavelength regions and lower production cost. The heterojunction of amorphous and crystalline silicon combines a favorable absorption characteristic for the solar spectrum and could reduce the amount of silicon used due to overall thinner films. For sample preparation, thin layers of amorphous silicon (a-Si) were prepared by magnetron sputtering in high vacuum on HF-etched p-type crystalline silicon (c-Si). During the sputtering process deposition parameters like temperature, hydrogen flow rate and film thickness of the amorphous film were varied. Using ohmic Nickel-Chromium back and front contacts, the samples were investigated by temperature dependent I-V characterisation and measurements under illumination using a solar simulator. Especially the influence of hydrogen flow rate on the current voltage (I-V) characteristics, barrier heights and thermal activation energies are shown in relation with cell efficiencies.