A general device concept based on the miniband junctions formed in superlattices is described. Just as heterojunctions play an important role in bulk semiconductor devices, the miniband junctions have potential applications for superlattice devices. In the band-aligned structures, the aligned minibands function as an energy filter, which ensures efficient injection of monoenergetic carriers, while the miniband offsets can block the carrier flow similarly to the band discontinuity in bulk heterostructures. By engineering the alloy composition, the layer width, the doping, and the applied electric field, several examples of band-aligned superlattices are analyzed for applications in miniband transport and intersubband transitions. >