Getting Started with XPS Peak Fitting: Questions and Answers

[Montserrat Crespo]

Hi, guys.

I'm beginning to fit XPS peaks from a environmental measurement but, as I'm unfamiliar with the exact process I have a lot of doubts. I have solved some of them using the info in http://xpssimplified.com/periodictable.php and in the XPS manual from Moulder and Stickle but I'm not sure if I'm making it right.

The question is: how do I know if in the sample is present an element? I mean, I know I should check for the difference between 2p1/2 and 2p3/2, por example, but this is the accurate way to make it? If the difference is approximately the same that is presented in the literature but the ratio is not, is still the element there? What else should I look for?

Thank you very much for your help.

 

[Achy47]

Hi there,

As a scientist who has experience with fitting XPS peaks, I can offer some guidance on your questions. First of all, congratulations on taking on this project and seeking out resources to help you with the process. It's always important to make sure you fully understand the techniques and methods you are using.

To answer your first question, the accurate way to determine if an element is present in your sample is by comparing the binding energy of the 2p1/2 and 2p3/2 peaks to the literature values. As you mentioned, the difference between these two peaks should be consistent with the literature values for that element. However, it's important to note that the ratio between the two peaks can also vary depending on factors such as sample preparation and instrument calibration. Therefore, it's best to compare the overall shape and position of the peaks to the literature values as well.

In addition to comparing the peaks to literature values, you should also look at the overall spectrum to see if there are any other peaks present that correspond to the element you are looking for. For example, if you are looking for the presence of carbon, you would expect to see peaks at 284 eV for C1s and 532 eV for O1s. If these peaks are not present, it may indicate that the element is not present in your sample.

It's also important to keep in mind that XPS is a surface-sensitive technique, so the results you obtain may not accurately represent the bulk composition of your sample. Therefore, it's always a good idea to confirm your findings with other techniques, such as SEM-EDX or X-ray diffraction.

I hope this helps answer your questions. If you have any further doubts or concerns, don't hesitate to consult with other experts in the field or refer to additional resources. Good luck with your XPS analysis!