Have you read any "old school" sci-fi like 2001: A Space Odyssey , Stranger In A Strange Land, and Foundation books? The authors of these 3 books (Arthur C Clarke, Robert Heinlein, and Isaac Asimov) were all scientists and quite a few of their books are classics.
The classic book of sci-fi, which you have to read if you haven't already, is Dune. Forget the movie and the tv series, this is one book you must read.
I really like Philip K Dick, too. His wit & mind-boggling plots are truly singular.
Sci-fi has taken a different turn in the last 20 years or so, starting with William Gibson's book Neuromancer (where he coined the term "cyberspace"). His initial books are very good (Idoru , Mona Lisa Overdrive etc) although he went off the rails with the last few, imho.
Then came Neal Stephenson and he is now probably the most consistently brilliant sci-fi writer out there. His Snow Crash was selected into Time magazine's "100 Best English Language Books of All Time" list (there wasn't much sci-fi there). Among his books, Diamond Age, Cryptonomicon, and more recently Anathem are all masterpieces.