Contact professors regarding a not registered invention idea I have received my MSc degree and I want to apply for Ph.D. programs. 

I have an idea for an invention (this idea came from my master’s thesis), but it is not completely related to my field – I will need help from people of other fields to design this application.
The idea is new and it is not registered yet.

Since I am graduated, I don’t have any access to the university.
How should I approach a professor to team with me for this work? Is it possible?
If yes could you please give me a piece of advice or sample emails?

BWY, I'd like to study in a foreign country as well, e.g., in the USA.
You can always contact professors in order to team up, however it will probably be the case that they will provide PhD students to team up with you. This is just a matter of communication and I don't think that is the real problem here.

The idea not being registered yet raises the real issue, because if you start to emailing everybody to try find a team someone may find the idea interesting and start working on it. Then comes the question is it possible to register the idea like in a patent or something? If not, is it possible to publish a paper about it on a conference, this would be a way to turn the idea public but with an authorship kept.

Another thing related to the team item is that you should first get an adviser and be accepted for a PhD program and then you should worry with the team up for the implementation, maybe even with your adviser help.