If you have Physics as one of the subjects in your UG with Mathematics for at least 1 year then you are eligible for the IIT JAM Physics paper. If you have Mathematics as one of the subject in your UG for the 3 years then you are eligible for the IIT JAM Mathematics paper.

If you want to go for the research in Electronics and Semi Conductors, then go for the MSc Physics course. After that you can go for the research in the fields of Stat Mech or Condensed Matter Physics or Electronics or Semiconductor Physics and Material Sciences which are very close fields and can full fill your aspirations. So going for Physics will be a better choice if you want to go for research in Electronics and Semiconductors.

To know more about IIT JAM visit the link below:

https://university.careers360.com/exams/jam

I hope this answer helps. All the very best for your future endeavors!