Scanning near-field electron beam induced current microscopy: Application to III-V heterostructures and quantum dots

High resolution electron beam induced current (EBIC) analyses were carried out on InAs quantum dots (QDs) grown on GaAs substrate, in a scanning electron microscope (SEM) and a conducting atomic force microscope (C-AFM) hybrid system. This scanning near-field EBIC microscope allows one to image a sample conventionally by SEM, to investigate by AFM the local topography and to simultaneously perform EBIC imaging. The EBIC capabilities of this combined instrument are evidenced by imaging plastic slip lines created by nanoindentation, and its performance in resolution is demonstrated to be of the order of 20 nm by imaging the induced current flowing through the InAs/GaAs QDs and the ringlike structures that surround them. The influence of the presence of QDs on the minority carrier diffusion length is also investigated. It is shown that the presence of QDs close to the surface sample increases the diffusion length. (c) 2007 American Institute of Physics.