Table 2. High Resolution of O 1s Core-Level Values for the (a) Undoped, Co-, Mn-, and Cu-Doped ZnO Nanostructures.

	O1		O2		O3		Olattice/Osurface
sample	binding energy (eV)	area (%)	binding energy (eV)	area (%)	binding energy (eV)	area (%)	O1/O2
pure ZnO	528.9	17.2	530.4	12.3	532.2	1.3	1.4
ZnO:Co	528.9	14.5	530.9	14.2	532.9	2.7	0.9
ZnO:Mn	529.8	21.3	531.3	13.1	532.8	1.2	1.6
ZnO:Cu	529.0	20.4	530.9	12.6	532.9	1.2	1.6