Measurement of the second-order susceptibility of GaInP films at 1.5 μm

This paper reports measurements of the second order susceptibility in Ga0.5In0.5P films. The key feature is the difference between the dij matrices for ordered and disordered GaInP. The symmetry of ordered GaInP is triagonal C3v with alternatively ordered Ga-rich and In-rich planes in the [1¯,1,1] direction, while that of disordered GaInP is Td, (like GaAs). It is possible to periodically disorder GaInP and modulate five of the eight nonzero d coefficients between their nominal values (ordered phase) and zero-value (disordered phase). It is believed that the 7% difference between the lattice constants of GaP (5.45 angstrom) and InP (5.87) crystals implies a large spontaneous polarization and thus large modulatable χ(2) components.