Well, they can't be compare. Because unicode is a single character set that match a number for every character in the world written system. UTF-8, in another hand, is an encoding algorithm to store the unicode number on disk. There are many encoding algorithm beside UTF-8, ie ASCII, EBCDIC, etc.., but, there is only one Unicode system for all these encoding algorithm.
I really like the following posts that tell us about Unicode and UTF-8
Some list of unicode code page