OPTOELECTRONIC PROPERTIES OF TRANSITION-METAL AND RARE-EARTH-DOPED EPITAXIAL LAYERS ON INP FOR MAGNETOOPTICS

Rare earth- and transition metal-doped thin films of InP, In0.53Ga0.47 As, and In0.71Ga0.29As0.58P0.42 were grown by liquid phase epitaxy and evaluated for use in integrated electro-optical and magneto-optical a pplications, such as waveguides and Faraday rotators. The films were l attice matched to (100) InP substrates, and the transition metal (Mn) and rare earth (Gd, Eu, and Er) doping concentrations were between 2.6 x 10(18) and 1.5 x 10(20) cm(-3). The chemical profiles were generall y found to be homogeneous by SIMS, although in more highly doped films the rare earths were observed to segregate toward the interfaces. The undoped films were n-type, and the net carrier concentrations in the rare earth-doped (Gd, Eu, Er) films were decreased by an order of magn itude. The Mn-doped films were p-type. Optically, the rare earth dopan ts were observed to raise the refractive index of the layers at 632.8 nm, and subsequent waveguiding in doped InP layers was observed at 1.3 mu m. Although the Faraday rotations of our materials were much less than that of well known oxides, such as yttrium iron garnet, they were sufficient for device applications, and our materials can be much mor e easily integrated with InP OEIC devices. For example, a 1 cm wavegui de would provide the large rotation (45 degrees) required in isolator applications.