In.sub.xAl.sub.yGa.sub.1-x-yN semiconductor structures having optoelectronic elements characterized by epitaxial layers having different in-plane a-lattice parameters and different InN mole fractions are disclosed. The active regions are configured to emit radiation in different wavelength ranges and are characterized by strain states within about 1% to 2% of compressive strain. The epitaxial layers are grown on patterned In.sub.xAl.sub.yGa.sub.1-x-yN seed regions on a single substrate, where the relaxed InGaN growth layers provide (0001) In.sub.xAl.sub.yGa.sub.1-x-yN growth surfaces characterized by different in-plane a-lattice parameters and different InN mole fractions. In.sub.xAl.sub.yGa.sub.1-x-yN semiconductor structures can be used in optoelectronic devices such as in light sources for illumination and in display applications.