摘要： The success of the semiconductor industry originates from the ability to precisely tune the electronic properties of semiconductor materials. Different approaches are used to enhance the functionality of semiconductors, such as impurity doping, alloying, heterostructuring, and straining. All these methods are based on the addition of chemical elements to a pure semiconductor. An important example is the invention of the GaAs/AlGaAs heterostructure, which has enabled the development of laser diode and high-electron-mobility transistor (HEMT). In this chapter, we will discuss the combination of two different classes of semiconductors, group IV, like Si and Ge, and group III–V, like GaAs and InP. We will focus on a relatively new materials system, i.e., nanowires (NWs), in which strain can be effectively relieved at the surface due to the small dimensions, therefore relaxing the requirements on lattice matching. This system thus offers enhanced flexibility over the conventional layered structures in combining different semiconductor materials. These new combinations may boost the performance of already widely explored device concepts, such as transistors and solar cells, but may also open new applications, such as in quantum information technology. After a discussion on the different challenges related to the combination of Si and III–V semiconductors, we will discuss the growth of III–V nanowires on group IV substrates, and then focus on the growth of heterostructures within nanowires in the radial and axial directions.