A microelectronic device provided with one or more quantum wires, able to form one or more transistor channels, and optimized in terms of arrangement, shape, and/or composition. A method for fabricating the device includes forming, in one or more thin layers resting on a support, a first block and a second block in which at least one transistor drain region and at least one transistor source region are respectively intended to be formed, forming a structure connecting the first block to the second block, and forming, on the surface of the structure, wires connecting a first region of the first block with another region of the second block that faces the first region.