ACTA

Reduction of the Optical Losses in CdTe/ZnTe Thin-Film Solar Cells

S. Chusnutdinow^a, R. Pietruszka^a, W. Zaleszczyk^a, V.P. Makhniy^b, M. Wiater^a, V. Kolkovsky^a, T. Wojtowicz^a and G. Karczewski^a
^aInstitute of Physics, PAS, al. Lotników 32/46, 02-668 Warszawa, Poland
^bYuri Fedkovych Chernivtsi National University, 2 Kotsyubynsky Str., 58012 Chernivtsi, Ukraine

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We report on reduction of optical losses in n-CdTe/p-ZnTe thin-film solar cells grown by molecular beam epitaxy. The investigated thin-film devices were grown from elemental sources on monocrystalline, semi-insulating, (100)-oriented GaAs substrates. The optical losses have been reduced by a texturing of the device surface and by depositing of a ZnO antireflection coating. Current-voltage and spectral characteristics of the investigated p-ZnTe/n-CdTe solar cells depend significantly on the preparation of the surface of the ZnTe window. We describe a procedure of chemical etching of the ZnTe window leading to surface texturing. A ZnO layer of proper thickness deposited by low-temperature atomic layer deposition technique on the ZnTe surface forms an effective antireflection coating that leads to the reduction of optical losses. Due to reduction of the optical losses we observe increase of the short-circuit current, J_SC, by almost 60% and of the energy conversion: efficiency by 44%.

DOI: 10.12693/APhysPolA.126.1072
PACS numbers: 81.15.Hi, 73.61.Ga, 85.60.Dw, 88.40.jm