Noone is going to do your research for you and no-one is going to write your dissertation except yourself. Are there any gaps in information?
You may also like. Concede that an existing point of view has certain merits but that it needs to be qualified in certain important respects. Read a lot and do the research. On the other hand, if your dissertation is to be based on secondary non-empirical data then you can simply stick to existing literature in your area of study.
And make sure to summarize viewpoints and findings of other researchers in the dissertation literature review chapter.
To this I would add that a dissertation is an extended piece of academic writing that challenges you, under the guidance of a supervisor, to participate independently in the academic discourse. When you come back to it, you'll be able to notice most of its flaws.
The process of producing your writing plan could go as follows. Wikipedia is not a reliable source, but it can take you to some great publication if you check out the list of references on the pages of your interest.
Chapter s describing methods, sources, material etc In these chapters a straightforward description is required of how you conducted the research. It should be able to stand alone in representing why and how you did what you did, and what the results and implications are.
You don't want to end up with a too complex question that would trick you in a dead end.
It might also be data that others have collected but is still in its raw form.