Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 92: Poster Session: Structure and transport in organic photovoltaics; Photovoltaics; Impurities/Amorphous semiconductors; New materials

HL 92.15: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Thin film GaN/Cu2O heterojunction solar cells — •Philipp Hering, Julian Benz, Daniel Reppin, Martin Becker, and Bruno Meyer — 1. phys. Inst., JLU-Giessen, Heinrich-Buff-Ring 16, 35392 Giessen

Due to its high absorption coefficient, non-toxicity, and the abundance of its composing elements, cuprous oxide (Cu2O) is a promising absorber material in photovoltaic devices, even despite of the relatively large band gap (2.17 eV). With increasing success, more attention has recently been paid to Zinc Oxide/Cuprous Oxide heterojunctions. At higher forward voltages, however, the large conduction band offset impedes the minority carrier current across the interface: The theoretically attainable efficiency is decreased by about 50%. As a way out, we chose Gallium Nitride as window layer: It offers a conduction band offset of less than 0.2 eV in relation to Cu2O. Our cells were manufactured at room temperature by radio frequency sputter deposition of cuprous oxide, utilizing a copper target under addition of oxygen on top of Gallium Nitride templates. The templates consisted of a thin layer of GaN:Si, grown on a sapphire substrate by metal organic chemical vapor deposition. The sputtering was followed up by photolithographic structuring. For device characterization Current/voltage curves were obtained under AM1.5g illumination, different light intensities, as well as various temperatures, and the external quantum efficiency measured.