Nanometer-Scale Current-Voltage Spectra Measurement of Resonant Tunneling Diodes Using Scanning Force Microscopy

Abstract

We demonstrate that a novel method of current-voltage (I-V) spectra measurement by scanning force microscopy (SFM) reveals local electrical characteristics of resonant tunneling diodes (RTDs) on a nanometer scale. Measured SFM I-V spectra of RTDs show negative differential resistance features, and the spatial resolution of this method was found to be 20 nm. Experimental evidence for the quantized nature of an SFM pointcontact was observed for the first time. High spatial resolution of this method was confirmed by a simple calculation for the area of current flow through RTD. Fine structure in the SFM I-V spectra was also observed.