Sputtering-assisted metal-organic chemical vapor deposition of Yb-doped ZnO for photonic conversion in Si solar cells

We have grown Yb-doped ZnO (ZnO:Yb) on c-plane sapphire substrates by sputtering-assisted metal-organic chemical vapor deposition (SA-MOCVD). X-ray diffraction (XRD) revealed that these ZnO:Yb films exhibit a c-axis orientation and that the lattice constant increases with Yb concentration. After annealing the samples at 600 degrees C for 0.5 h in O2, they showed a clear 980 nm emission due to the intra-4f shell transitions of F-2(5/2) -F-2(7/2) in Yb3+ ions. It turns out that Yb lu-minescent centers with different local structures coexist, which exhibit different energy transfer processes from the ZnO host. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)