A study on repeatable and universal growth morphology optimization for nanowires grown on Si substrates

In this work, a series of NWs growths with different treatments for substrate surface have been carried out to study growth morphology optimization for NWs grown on Si substrates. A substrate treatment method of high-temperature annealing combined with thin oxide layer formed on the substrate surface has been developed. It is found that a lot of crystal defects exist in random locations of common substrates surface which make it difficult to grow NWs, but easy to form parasitic islands. XRD and AFM show that high-temperature annealing process can effectively eliminate most of the crystal defects in the substrates, inhibit the formation of parasitic islands. Combined with forming thin natural oxide layer on the substrate surface, the density of InAs NWs can be increased, the growth morphology uniformity of InAs NWs on Si substrates can be improved and parasitic islands are rarely formed on the substrates surface at all. In order to verify the effectiveness and universality of this method, another experiment of InGaAs NWs grown at different temperatures obtained excellent growth results as well. Therefore, this substrate treatment method has good effectiveness, repeatability and universality in optimizing the growth morphology of NWs.