2. Properties of one-dimensional heterostructures

2.1 Simple heterostructures

Combining different materials and ensuring good interface quality remains a major technological challenge. It has long been known that a metallic contact on GaAs is of much better quality than on silicon, hence the development of MESFET and then HEMT transistors on III-V materials. Mastering semiconductor-oxide heterointerfaces in the same way was the priority for MOS transistors, a problem that is back on the agenda following the introduction of new high-permittivity dielectrics at gate level to further miniaturize these transistors. What's more, semiconductor heterostructures have become essential to optimize performance and keep up with the high-frequency race.