Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.60: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Semiconductor-Insulator-Semiconductor solar cells on wet-chemically etched silicon nanowire carpets using different tunnel barrier materials — •Martin Schreivogel1, Björn Hoffmann1, Gerald Brönstrup1, Vladimir Sivakov1, and Silke Christiansen1,2 — 1Institut für Photonische Technologien, Jena — 2Max-Planck-Institut für die Physik des Lichts, Erlangen
Nanostructured semiconductor substrates are an intensively investigated possibility to improve solar cell performance. For this purpose we prepare chemically etched silicon nanowire carpets with adjustable geometrical structure. The etching process is cheap and easily scalable, is performed at room temperature and uses no photolithography-step. The produced nanowire carpets show high absorption over a broad spectral range. The nanowires are used as substrate for semiconductor-insulator-semiconductor (SIS) solar cells. Therefore we generate a very thin layer of an insulating oxide on the nanowires and deposit a transparent conductive oxide (TCO) as top electrode. The insulating tunnel barrier is prepared either by chemically oxidizing the substrate material receiving silicon oxide or by depositing aluminium oxide by atomic layer deposition (ALD). Sputtered or ALD-Aluminum-doped zinc oxide (AZO) is used as TCO. We characterize the solar cells by I-V-curve measurements and calculation of the pseudo efficiency, which is reproducibly more than 8%. The structure of the produced devices is investigated by SEM and FIB. To prove the electrical contribution of the nanowires we performed electron beam induced current (EBIC) measurements on solar cell cross sections.