Electronic states of self-organized InGaAs quantum dots on GaAs (3 1 1)B studied by conductive scanning probe microscope

We have used conductive scanning probe microscope (SPM) in high vacuum and operated at View the MathML source in order to investigate the electronic properties of self-organized InGaAs quantum dots (QDs) grown on GaAs View the MathML source and (001) substrates. Ordered InGaAs quantum dot arrays on GaAs View the MathML source surface were fabricated by atomic-H assisted molecular beam epitaxy (H-MBE), and Si SPM tips coated with Au which warrants electrical conductivity were used to measure simultaneously both the topographic and current images of QDs surface. From the current–voltage (I–V) curves, unique and different plateau features were observed for QDs formed on GaAs View the MathML source and (001) substrates. The results suggested that a high degree of symmetry of InGaAs QDs on View the MathML source was responsible for the observed degeneracy of electronic states and artificial atom-like states. We demonstrate that this conductive SPM technique becomes a powerful tool in studies of single electron charging of individual dots.