Many students who have finished a research programme choose to continue at a PhD level. During the 4-year programme, PhD candidates conduct a research project culminating in a PhD thesis or a series of articles in scientific journals.
The candidates work under the supervision of a professor. Additionally, PhD candidates take courses at one of the Graduate Schools and must also provide teaching themselves.
Apart from applying to one of the available PhD positions, candidates having finished a graduate programme may also submit PhD research proposals of their own. Read more at the PhD candidates site.