  Quantum engineering entails atom by atom design and fabrication of electronic
devices. This innovative technology that unifies materials science and device
engineering has been fostered by the recent progress in the fabrication of
vertical and lateral heterostructures of two-dimensional materials and by the
assessment of the technology potential via computational nanotechnology. But
how close are we to the possibility of practical realisation of the next
generation atomically thin transistors? In this perspective we analyse the
outlook and the challenges of quantum- engineered transistors using
heterostructures of two-dimensional materials against the benchmark of silicon
technology and its foreseeable evolution in terms of potential performance and
manufacturability. Transistors based on lateral heterostructures emerge as the
most promising option from a performance point of view, even if heterostructure
formation and control are in the initial technology development stage.
