Nanoscale potential distribution across multiquantum well structures: Kelvin probe force microscopy and secondary electron imaging

Ultrahigh vacuum cross-sectional Kelvin probe force microscopy has been used to characterize In0.17GaAs/GaAsP0.06 multiquantum well structures, together with secondary electron microscopy. Individual 8 nm quantum wells were well resolved in both methods, and were found to be in a good agreement with numerical simulations of the work function profile. It is shown that the surface potential contrast in the Kelvin probe force microscopy measurements is greatly enhanced using deconvolution algorithms, and the reasons for the different contrast in the electron microscopy images are discussed.