I have to find the radius of convergence of the following complex series:

$$\sum\_{n=0}^{\infty} \frac{z^n}{(1-i)^n}$$

The radius of convergence I get its $R = \sqrt{2}$, now I have to examine what happens with this series on this edge, that is where $|z| = \sqrt{2}$.

Here is where my problems start, the absolute convergence doesn't help me as it doesn't converge absolutely, any tips on what path to follow on?

Thanks :)