Influence of Different Growth Methods on the Electrical Properties of InAs Nanowires
In this chapter, we have studied the similarity and difference between the electrical properties of InAs nanowires grown by two commonly used material growth systems, MBE and MOCVD. Bases on the statistical data of more than 70 InAs nanowires back-gated FETs whose diameter range from 16 nm to more than 100 nm, we find that when the diameter of InAs nanowires is relatively small, most of the MOCVD-grown InAs nanowires have similar electron mobility, threshold voltage, ON-state current, and OFF-state current with MBE-grown InAs nanowires. However, the dispersion of these electrical properties within the MOCVD-grown InAs nanowires is much larger than that within the MBE-grown nanowires. On the other hand, when the diameter of InAs nanowires is relatively large, the ON-state properties of MBE- and MOCVD-grown nanowires does not show obvious difference, but their OFF-state properties have apparently different features. The MOCVD-grown nanowires have smaller OFF-state resistance than the MBE-grown nanowires, and some of the large-diameter nanowires even show metallic behavior. By simulating the distribution of electrons under ON-state and OFF-state in the nanowires with various doping levels through the finite element model, we attribute the background carbon doping induced by the organic sources used in the growing procedures of MOCVD to be the main cause for the above differences. Our work has deepened the understanding of the relation between nanowire growth and device performance, and may be instructive for controlling the growth of InAs nanowires.