Well, here goes my answer:
1. What would be the career opportunities after M.Tech.?
You can join any govt or private sector or a research lab or R&D or any other departments of electronics or related industries.
2. How can I find whether I can do well in research field?
You will need to find out if you have an aptitude for research. Do you possess any of these traits: curiosity, creativity, innovativeness, patience, perseverance, documentation, logic, analysis etc.
3. Where are the best opportunities if research is considered?
R&D labs in govt and private sector.
4. How can I start to enhance my career?
Do an in depth research project in second year.