Self-powered photodetectors operating in the UV-visible-NIR window made of environmentally friendly, earth abundant, and cheap materials are appealing systems to exploit natural solar radiation without external power sources. In this study, we propose a new p-n junction nanostructure, based on a ZnO-Co3O4 core-shell nanowire (NW) system, with a suitable electronic band structure and improved light absorption, charge transport, and charge collection, to build an efficient UV-visible-NIR p-n heterojunction photodetector. Ultrathin Co3O4 films (in the range 1-15 nm) were sputter-deposited on hydrothermally grown ZnO NW arrays. The effect of a thin layer of the Al2O3 buffer layer between ZnO and Co3O4 was investigated, which may inhibit charge recombination, boosting device performance. The photoresponse of the ZnO-Al2O3-Co3O4 system at zero bias is 6 times higher compared to that of ZnO-Co3O4. The responsivity (R) and specific detectivity (D) of the best device were 21.80 mA W-1 and 4.12 × 1012 Jones, respectively. These results suggest a novel p-n junction structure to develop all-oxide UV-vis photodetectors based on stable, nontoxic, low-cost materials.
Ghamgosar, P., Rigoni, F., Kohan, M.G., You, S., Morales, E.A., Mazzaro, R., et al. (2019). Self-Powered Photodetectors Based on Core-Shell ZnO-Co3O4 Nanowire Heterojunctions. ACS APPLIED MATERIALS & INTERFACES, 11(26), 23454-23462 [10.1021/acsami.9b04838].
Self-Powered Photodetectors Based on Core-Shell ZnO-Co3O4 Nanowire Heterojunctions
Rigoni F.;Mazzaro R.;Morandi V.;
2019
Abstract
Self-powered photodetectors operating in the UV-visible-NIR window made of environmentally friendly, earth abundant, and cheap materials are appealing systems to exploit natural solar radiation without external power sources. In this study, we propose a new p-n junction nanostructure, based on a ZnO-Co3O4 core-shell nanowire (NW) system, with a suitable electronic band structure and improved light absorption, charge transport, and charge collection, to build an efficient UV-visible-NIR p-n heterojunction photodetector. Ultrathin Co3O4 films (in the range 1-15 nm) were sputter-deposited on hydrothermally grown ZnO NW arrays. The effect of a thin layer of the Al2O3 buffer layer between ZnO and Co3O4 was investigated, which may inhibit charge recombination, boosting device performance. The photoresponse of the ZnO-Al2O3-Co3O4 system at zero bias is 6 times higher compared to that of ZnO-Co3O4. The responsivity (R) and specific detectivity (D) of the best device were 21.80 mA W-1 and 4.12 × 1012 Jones, respectively. These results suggest a novel p-n junction structure to develop all-oxide UV-vis photodetectors based on stable, nontoxic, low-cost materials.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
