A method for fabricating p-type, i-type, and n-type III-V compound materials using HVPE techniques is provided. If desired, these materials can be grown directly onto the surface of a substrate without the inclusion of a low temperature buffer layer. By growing multiple layers of differing conductivity, a variety of different device structures can be fabricated including simple p-n homojunction and heterojunction structures as well as more complex structures in which the p-n junction, either homojunction or heterojunction, is interposed between a pair of wide band gap material layers. The provided method can also be used to fabricate a device in which a non-continuous quantum dot layer is grown within the p-n junction. The quantum dot layer is comprised of a plurality of quantum dot regions, each of which is typically between approximately 20 and 30 Angstroms per axis. The quantum dot layer is preferably comprised of Al.sub.x B.sub.y In.sub.z Ga.sub.1-x-y-z N, InGaN.sub.1-a-b P.sub.a As.sub.b, or Al.sub.x B.sub.y In.sub.z Ga.sub.1-x-y-z N.sub.1-a-b P.sub.a As.sub.b.