The prospectus for the doctoral dissertation is a document which describes the problem of one's research, how the related research informs and relates to the study, and the details of the methodology. The prospectus should consist of three chapters, organized as follows:
Chapter 1: The Problem--This chapter describes the problem of your research and includes the research questions that will guide the study. It also includes a discussion of the rationale for the study and connections to the related research. The chapter should clearly identify the problem, the research questions, rationale, and methodology.
Chapter 2: Literature and Research--This chapter should contain a discussion of the literature and research related to your study and should clearly identify the research findings related to the major variables of your study. Look carefully at your research questions, and identify the key topics (variables?) that are implicit in the questions. Your chapter should be organized in a way that logically presents the findings in research related to these topics (variables), and how these findings inform and relate to your study. You should draw conclusions from the research for each of the sub-sections of your chapter. You might also think of the this chapter as describing the context of your research.
Chapter 3: Methodology--This chapter is an in-depth discussion of the research methods that you have selected to use in your study. The chapter should include a discussion of the rationale for your selection of research methods, your role as a researcher, a discussion showing a clear link from your research questions and the research methods, a discussion of your participants (or population/sample), how they were selected, and a discussion of how you will collect, analyze and interpret your data.
I have put up on the web examples of science education dissertation prospectus' that you should find useful as you plan your own study. Review one or more of the chapters for each prospectus and look carefully at the organization that each researcher used for their prospectus. You can contact these students and seek their wisdom on the generation of your own prospectus.