Figure 1.

aThe ZnO nanowire unit-cell andbbulk unit-cell are studied here. Thegrey spheresare Zn,yelloware O,redare H1.5, andblueare H0.5. Thegreen spheresare the Zn sites substituted with Cr atoms or other TM atoms. The geometry is before relaxation

Shi and Duan Nanoscale Research Letters 2009 4:480   doi:10.1007/s11671-009-9260-7