I have been fascinated by creative ideas that arise out of deep involvement and single minded pursuit in a particular subject and the consequential discoveries and applications.
There are too many "ands" in this sentence. I can barely make sense of it.
This has motivated me to involve myself in research and teaching in the future.
This isn't quite phrased correctly. You are not yet involved in research and teaching. So, you need to say something like, "this motivates me to become involved in research and teaching in the future."
However, I am not going to recommend that because it is just too dull.
I hope to fulfill my ambition in XYZ University which I consider as one of the best schools for research . I have gone through the brochures of XYZ very carefully and I have realized that the excellent research facilities and high standards of faculty will provide a perfect environment for me to focus all my mental resources and do independent research.
Either XYZ is a strong research institution or it is not. If so, it certainly doesn't matter whether you consider it to be so. If you have studied the university so extensively, then you ought to be able to say which of its ongoing research projects interests you and/or which professor or professors with whom you would like to work. Be specific!
Indeed, that is my recommendation for your introduction as well. You have many details in the body of the essay, but the introduction is vague and unfocused. Say something that decisively introduces you and/or your
specific research interests.