Type I to Type II superlattice transition in strained layers of In sub x Ga sub (1-x) As grown on InP.

Optical and electronic properties of In sub x Ga sub (1-x) As strained layer superlattices grown on InP have been investigated over the entire range of Indium composition, 0 x 1. We demonstrate a type I to Type II superlattice transition at x ~ 0.20. Below this critical concentration electrons become confined to the InP layer. Excellent agreement is obtained with the band structure calculation based on empirical relative valence band energies and deformation potential theory. This agreement suggests that the effect of strain on these relative energies is negligible.