(Invited) The Structure-Dependent Properties of InAs Nanowires and Their Devices

Abstract

InAs nanowire is an important III-V group semiconducting nanomaterial with direct and narrow bandgap and small effective electron mass. It has great potential in high-performance electronic nanodevices and infrared detectors. In this talk, I will introduce our recent progresses on the structure-dependent properties of InAs nanowires and their devices. Various properties of individual InAs nanowires are studied and correlated with their structures through a comprehensive in situ platform we have developed in a scanning electron microscope. Remarkable piezoelectric and piezoresistive effects are observed for the first time in single-crystalline <0001> WZ InAs nanowires, but negligible effect is found in WZ nanowires with other orientations and nanowires with ZB structures. An ultrafast and reversible electrochemical lithiation of InAs nanowires are observed for the first time. Field effect transistors (FETs) based on MBE-grown InAs nanowires are studied. Importantly, based on nano-manipulation and microlithography, we develop a new method to characterize the same individual InAs nanowires in the FETs by transmission electron microscopy to obtain the atomic-level structures. Our study shows that not only the diameter, but also the crystal structure and the orientation of the InAs nanowires remarkably affect the electronic properties of the FETs, such as the threshold voltage, On/OFF current ratio, on-state current, subthreshold swing and electron mobility, etc. Ohmic contact are obtained for the nanowires with different diameters down to 7 nm.