A monolithic electronic device includes a first nitride epitaxial structure including a plurality of nitride epitaxial layers. The plurality of nitride epitaxial layers include at least one common nitride epitaxial layer. A second nitride epitaxial structure is on the common nitride epitaxial layer of the first nitride epitaxial structure. A first plurality of electrical contacts is on the first epitaxial nitride structure and defines a first electronic device in the first nitride epitaxial structure. A second plurality of electrical contacts is on the first epitaxial nitride structure and defines a second electronic device in the second nitride epitaxial structure. A monolithic electronic device includes a bulk semi-insulating silicon carbide substrate having implanted source and drain regions and an implanted channel region between the source and drain regions, and a nitride epitaxial structure on the surface of the silicon carbide substrate. Corresponding methods are also disclosed.