As far as i know there are no active Phd programs in nanotechnology but this programs are very popular in Israel so i'm sure you can find a great program that will fit your needs. There are a few universities and other institutions in Israel that offer PhD programs to international students, among them a few that might be able to offer you a PhD program in nanotechnology: The Ben Gurion University, The Technion, The Haifa University, The Tel Aviv University and more. Each of those institutes have different admission but in general candidates will have to finish a Masters thesis track in a known academic institution in the world, their grade average must be at least 80 (B), and the thesis grade must be 85 or higher (the equivalent of "Very Good").
Iv'e attached a link at the end of my message to an article about the PhD programs in Israel, admission, institutes and more.