as the title, I want to know the complex representations of the B(2，$\mathbb{F}_p$'s algebraic closure) (invertible upper triangle matrix groups over $\mathbb{F}_p$'s algebraic closure)...

I know some irreducible representations of this group which can be constructed through Mackey method(B=AH...). But I do not know whether these irreducible representations are the whole irreducible representations. The original Mackey's method was established for finite groups， I don't know whether it can be extended to infinite groups.