...GaAs, like other semiconductor compounds used in diode lasers, is a directgap semiconductor in which the conduction band minimum and the valence band maximum occur at the same point in k-space (the F point, in the case of GaAs}. Hence, electronic transitions between these two band extrema...

...semiconductor materials (such as GaAs and other III-V compounds) have an energy-^ relationship such that the conduction band minimum and the valence band maximum occur at the same value of k, as shown in Fig. 5.1. With direct bandgap materials, the holes and electrons can recombine...