Question

The flat band diagram can distinguish between a direct and an indirect bandgap semiconductor

Answer 1

The flat band diagram doesn't distinguish between direct bandgap semiconductor and indirect bandgap semiconductor.

As you know, flat band is the daigram by which we can explain what is Energy gap between empty conduction band and filled valance band.in case of direct bandgap semiconductor and indirect bandgap semiconductor energy gap is same.so, this daigram is unable to distinguish between them.

Here in attachment, you can see that flat band daigram couldn't identity direct and indirect bandgap semiconductor , because both have same energy gap between empty conduction band and filled valance band.
But E vs K space daigram can distinguish between it .

Hence, option (2) False is correct