Selectively doped regions can be created either by implantation, diffusion, or epitaxial deposition of silicon. InP is also used as a substrate for epitaxial indium gallium arsenide based opto-electronic devices. In 2015 researchers used graphene to create biosensors with epitaxial graphene on silicon carbide. These transistors are often fabricated on p/p silicon epitaxial layers. It has also been used as a silicon dopant in epitaxial layers. Electrical resistance in 40-nanometer-wide nanoribbons of epitaxial graphene changes in discrete steps. The surface of epitaxial wafers may be textured to enhance light absorption. The new layers formed are called the epitaxial film or epitaxial layer. MODFETs can be manufactured by epitaxial growth of a strained SiGe layer. Brookite and rutile may grow together in an epitaxial relationship. Precise control over this step is essential to avoid the formation of defective epitaxial Si. Advanced processes such as epitaxial growth are possible. The duo started by setting up the epitaxial process at Santa Clara. Epitaxial graphene films can be grown on various crystalline surfaces. Epitaxial graphene growth on silicon carbide is wafer-scale technique to produce graphene.