Enhancing electrical properties of selectively grown in-plane InAs nanowires using InGaAs buffer and capping layers

In-plane semiconductor nanowires with complex branched geometries, prepared via selective area growth (SAG), offer a versatile platform for advanced electronics, optoelectronics, and quantum devices. However, defects and disorder at the interfaces and top surfaces of the nanowires can significantly degrade electrical properties. One effective method to mitigate these issues is the incorporation of buffer and capping layers with close lattice matching. In this work, we utilized InGaAs as buffer and capping layers for SAG InAs nanowires after expanding the growth selectivity window for InGaAs in the presence of atomic hydrogen. Hall measurements on InAs nanowires, with and without InGaAs buffer and/or capping layers, revealed that incorporating closely lattice-matched InGaAs buffer and capping layers nearly tripled the electron mobility and doubled the phase coherence length compared to nanowires without these layers. The InGaAs capping layer enables transparent interfaces between the superconductor and nanowire, facilitating superconductor–semiconductor hybrid devices. These findings highlight that the use of InGaAs buffer and capping layers is a crucial strategy for significantly enhancing the quality of InAs nanowires, unlocking their full potential for high-performance electronics and quantum devices.