After forming a buried nanowire segment surrounded by a gate structure located on a substrate, an epitaxial source region is grown on a first end of the buried nanowire segment while covering a second end of the buried nanowire segment and the gate structure followed by growing an epitaxial drain region on the second end of the buried nanowire segment while covering the epitaxial source region and the gate structure. The epitaxial source region includes a first semiconductor material and dopants of a first conductivity type, while the epitaxial drain region includes a first semiconductor material different from the first semiconductor material and dopants of a second conductivity type opposite the first conductivity type.