I would like to ask about the possibility of getting a paid PhD position in Germany. I am going to defend my thesis in Physics after a few days and I am thinking of applying for a PhD. My specialization is in nano-science and surface physics. The average of my Master's degree will be at most 2.7, which is between good and satisfactory. Does the average play a pivotal rule ? Is it difficult to get a paid PhD position?
Good grades can help, but they aren't the be all and end all. If you put together a great CV and have positive references then you've got a good chance of gaining an interview.
More important than grades I think is simply showing that you are, and will be, a good researcher. Not every great academic was a hotshot from Harvard in their undergrad years. And not everyone with a perfect GPA from Harvard would make a good academic.
I can tell you from personal experience that you don't need amazing grades to get a PhD scholarship. Just put your best foot forward in proving that you're an excellent researcher and go for gold.
Is it difficult to get a paid PhD position?
In Germany, most PhD positions are paid. In physics, you would typically get a half to three quarters full-time equivalent position as a university employee. I don't think it's particularly difficult to get such a position, if you have the right qualification for it. This will also depend on the place where you got your Master's degree.
Does the average play a pivotal rule?
A lot of professors that I know do care for good grades. And many university regulations ask for at least a good degree for admission as a PhD student (in my place, that translates to 2.5 or better, though there's a tolerance for students from abroad to take care of differences in the grading systems).
My suggestion would be to look for position being announced through for example in:
and apply or get in contact with the person there to see how far you can get.
Also try to use your personal network: Ask your supervisors whether they know good labs to apply to, or whether they could even throw in a word for you.
From my personal experience (just started a Ph.D. in theoretical physics in Hannover), it is not difficult. As @silvado mentions, most Ph.D. positions are paid with about 75 % equivalent of a university employee (corresponding to about 1500-1600 EUR after tax per month). You can look at the Internet for open positions or try and contact group leaders that you would like to work with (possibly after a consultation with your current supervisor). The latter, however, might require some time as the professor will need to find funding.
Regarding grades, some professors might care. In my case, that was not the case and only my research results (i.e., my master thesis) were important. Nevertheless, that is just a single experience and it might be different elsewhere. Anyway, I guess you can always ask about this and, if you can reasonably explain why your grades are not better, this might not be a serious issue.