The "2D" used here refers to something completely different than to what "2D" and "3D" refer when discussing CMOS transistors. All CMOS transistors, regardless

The "2D" used here refers to something completely different than to what "2D" and "3D" refer when discussing CMOS transistors. All CMOS transistors, regardless if they use a 2D geometry or a 3D geometry are made with silicon. Silicon is a 3D semiconductor material. For silicon to behave as a semiconductor, there must exist a big enough volume of material, with several atom layers in all the three directions of the space. Besides 3D semiconductor materials, there exist also 2D semiconductor materials, which consist of sheets that have a thickness of only one atom, for instance molybdenum disulfide, tungsten disulfide or graphene. In such 2D semiconductor materials, it is enough to have several atom layers in only two directions of the space, while in the third the thickness is of only one atom, i.e. the smallest possible. The article shows a very important progress in the direction of enabling the making of integrated circuits that use 2D semiconductor materials instead of silicon.