Structural and electrical characteristics of the GaAs1-xPx / GaAs and GaAs/GaAs1-xPx/GaAs (x=0.02, 0.05, 0.08, 0.16 and 0.32) hetero-epitaxial systems have been investigated using X-ray rocking curve technique, Optical Beam Induced Current imaging, Nomarski Micrograph, and I-V-T and C-V measurements. The rocking curve Full Width Half Maximum of the GaAs1-xPx epilayer increased sharply at x=0.16 due to a decreased layer thickness and increased in-plane mismatch. The cross-hatched line density in the OBIC image and Nomarski Micrograph increases as the lattice mismatch increases. The epilayer surface morphology is dependent on the layer thickness. The forward I-V characteristics of Au-GaAsP/GaAs and Au-GaAs/GaAsP/GaAs Schottky diodes showed an increased tunneling current for an the increased lattice mismatch. For GaAsP/GaAs structure with a higher phosphorus composition, Fermi-level pinning caused by misfit dislocation was observed. Au-GaAs/GaAsP/GaAs Schottky diodes show an excess current at the low temperature, high field range which, we believe, is due to defect related tunneling.