You need to get the XPS data of your thin films ans after that you will be able to calculate their atomic percentage.

Alternatively, if you want to dig deeper into the material, SIMS would be an option, but in that case you need a standard, of course.

To calculate the atomic percentage of lead (Pb) in a SnO2 film when doping at 0.2 at%, you can use the following formula:

Atomic Percentage of Pb = (Doping Concentration of Pb / Total Concentration of SnO2) * 100

Where:

- Doping Concentration of Pb: 0.2 at% (0.002 as a decimal)

- Total Concentration of SnO2: 100 at% (1.0 as a decimal), since SnO2 is the host material and you're calculating the atomic percentage within it.

Plugging in the values:

Atomic Percentage of Pb = (0.002 / 1.0) * 100

Atomic Percentage of Pb = 0.2%

So, when doping 0.2 at% of Pb into a SnO2 film, the atomic percentage of Pb will be 0.2%.