Table 6: Typical RBS and PIXE trace element concentrations in ppm (2,0 MeV H+; Ø 0,4 mm; 50 μC) of three ZnO+2%MgO PLD targets prepared from 99.995% ZnO and 99.998% MgO powders. The initial powders were homogenized in ball mills with three different grinding beakers, as indicated in the first column. Obviously, there is nearly no influence of the beaker material on the trace element impurities within the detection limits. Concentrations with “<” are below the detection limits of the analysis; for Si the detection limit is ~300 ppm, similar to tungsten.

ZnO + 2 % MgO targets milled in:TiCrFeCoNiZrW

WC beaker 1 7 ± 5 1 5 ± 4 3 6 ± 6 <14<24<49<317
ZrO2 beaker 1 5 ± 5 <5 4 2 ± 6 <14<23<46<309
SiO2 beaker
front side*
1 2 ± 4 <5 4 7 ± 7 <14<24<49<321
SiO2 beaker
back side*
1 6 ± 5 <5 5 2 ± 7 <14<24<47<319

*Front and back side refers to the side of the PLD target. Front side was ablated already for film growth.