IMAGING AND SPECTROSCOPY ELF SINGLE INAS SELF-ASSEMBLED QUANTUM DOTS USING BALLISTIC-ELECTRON-EMISSION MICROSCOPY

Single InAs self-assembled quantum dots buried spatially beneath a Au/ GaAs interface are probed for the first time using the imaging and spe ctroscopic models of ballistic electron emission microscopy (BEEM). BE EM images show enhanced current through each dot. Spectra taken with t he tip positioned on a dot show shifted current thresholds when compar ed with the off dot spectra, which are essentially the same as those o f Au on bulk GaAs. Shifts in the Gamma and L conduction band threshold s are attributed to strain in the GaAs cap layer. Fine structure below the Gamma threshold is consistent with resonant tunneling through zer o-dimensional states within the quantum dots.