Ordered Gallium Indium Phosphide as a New Nonlinear Optical Material

We propose development of ordered Ga1-xInxP grown by metalorganic chemical vapor deposition (MOCVD) on GaAs as a material showing very strong nonlinear optical (NLO) effects. With a bandgap of approximately 1.85 eV, lattice-matched, ordered Ga1-xInxP (x = 0.49) is useful as an NLO material with light from GaAs-based lasers. Although most III-V alloys have been found to show ordering effects under certain growth conditions, it is well known that MOCVD-grown Ga1-xInxP displays very strong ordering of the Ga- and In-sublattices along (111)-type directions, and that the degree of ordering is controlled by growth parameters; strong ordering should lead to the large birefringence needed for NLO applications. A film grown on a (100) GaAs substrate will have the optical ("C") axis of the material at an angle of 54.7 degrees to the wafer surface, thus enabling tuning of an NLO system by simple rotation of the Ga1-xInxP film with respect to the incoming laser. Phase I will detemine deposition parameters which yield the greatest degree of ordering, and the strongest nonlinear optical effect. Measurements will include atomic ordering and birefringence versus growth conditions. Phase II will optimize the growth of Ga1-xInxP so that the second-order nonlinear-optical susceptibility and birefringence are maximized. We will then design, fabricate, and test a GaAs-Ga1-xInxP device which utilizes the NLO properties, such as an optical parametric oscillatoar. Development may be extended to (A1yGa1-y) 0.5In0.5P to increase the bandgap.