DFT Investigation of the Heterostructure GaP(001) on Si(001)

Semiconductor multilayers are a versatile tool in optoelectronics. The III-V/IV heterostructure GaP(001) on Si(001) provides an almost lattice-matched stack which may serve as material for device applications such as multi-junction solar cells. One major challenge there arises from the efficiency limitations due to symmetry breaking and further structural imperfections at the buried interface between GaP and Si. Here, we study the influence of the local structural properties at the GaP/Si(001) interface on the stability and electronic states of the interface by ground state density-functional investigations. The study distinguishes between the Ga-rich and the P-rich interface termination of GaP in the (001) plane. For a perfectly flat interface, the P-rich variant exhibits higher stability than the Ga-rich one. The findings for atomic displacements at the interface are supported by the features of the local electronic system. The observed band bending exhibits characteristic features, which depend on the Ga or P interface termination. Further, the impact of the perfectly flat interface on the structural and electronic properties of the semiconductor slabs is very local.