High-quality vertically aligned InAs nanowires grown by molecular-beam epitaxy using Ag-In alloy segregation

InAs nanowires show important potential applications in novel nanoelectronic devices, infrared optoelectronic devices and quantum devices, and all these applications require controllable growth of the InAs nanowires. However, the growth direction of metal-assisted InAs nanowires on Si substrates is often random. Here, we develop a new approach to grow vertically aligned InAs nanowires on Si (111) substrates by molecular-beam epitaxy using Ag as catalysts. The vertically aligned one-dimensional InAs nanowires are grown on the parasitic two-dimensional InAs film on the Si substrates by using the Ag nanoparticles segregated from Ag-In alloy catalysts. The diameters of the vertically aligned InAs nanowires obtained by this method are mainly distributed between 20 and 50 nm. Detailed transmission electron microscope data show that the nanowires with thinner diameters tend to have less stacking faults and twin defects and high crystal quality pure wurtzite nanowires can be obtained. Using these vertically aligned InAs nanowires as the channel material of field effect transistors, we have obtained a field-effect mobility of similar to 2800 cm(2) V-1 s(-1) and an I (on)/I (off) ratio of similar to 10(4) at room temperature. Our work provides a new method for the controlled growth of high-quality vertically aligned InAs nanowires on Si substrates.

Automated summary

We have developed a new approach to grow vertically aligned InAs nanowires on Si (111) substrates using Ag as catalysts. The diameters of the nanowires obtained by this method are mainly distributed between 20 and 50 nm, and the nanowires with thinner diameters have fewer stacking faults and twin defects, allowing the production of high-quality pure wurtzite nanowires. By using these vertically aligned InAs nanowires as the channel material of field effect transistors, we achieved a field-effect mobility of about 2800 cm(2) V-1 s(-1) and an I (on)/I (off) ratio of about 10(4) at room temperature.