interaction design – Can I use semi-structured interviews for collecting insights for a prototype?

I have a low-fidelity prototype and I would like to use semi-structured interviews to ask users questions while having a walkthrough of the prototype.
Do you think it’s a good idea to choose semi-structured interviews or should I rather go with structured interviews?

So currently I am in the phase where I have finished the first version of the prototype and tested it using heuristics evaluation, now I would like to gather more information from users so I can refine the user requirements and consequently the prototype.

Prototyping -> Heuristics evaluation -> Semi-structured interviews -> Refine requirements -> Re-design prototype