If you are ready to start the PhD program, you probably know more about HRM than I do. Writing your dissertation has something in common with writing an admissions essay: it is something you MUST write to achieve a goal.
However, isn't it true that at a fundamental level we write an essays or articles out of sheer inspiration? It is backwards when people grope around for topics to write about. You should start by doing some reading. What are the three most interesting professional journal articles you have read about HRM. List 3 articles written in professional journals in the past 4 years or so, and it will help me to know your particular interests within the field.
You can use growth, progression, expansion, elaboration, evolution,... It depends on what you really mean with the word. Just so you know, you can google for stuff like this.
