Techniques and mechanisms for providing a complementary metal-oxide-semiconductor (CMOS) circuit which includes a group III-nitride (III-N) material. In an embodiment, an n-type transistor of the CMOS circuit comprises structures which are variously disposed on a group III-N semiconductor material. The n-type transistor is coupled to a p-type transistor of the CMOS circuit, wherein a channel region of the p-type transistor comprises a group III-V semiconductor material. The channel region is configured to conduct current along a first direction, where a surface portion of the group III-N semiconductor material extends along a second direction perpendicular to the second direction. In another embodiment, the group III-N semiconductor material includes a gallium-nitride (GaN) compound, and the group III-V semiconductor material includes a nanopillar of an indium antimonide (InSb) compound.