Cross-Sectional Potential Imaging of Compound Semiconductor Heterostructure by Kelvin Probe Force Microscopy

The cross-sectional potential images of the GaAs/AlAs multiple quantum wells and InAlAs/InGaAs heterostructures have been successfully obtained by Kelvin probe force microscopy (KFM). It was shown that the smaller amplitude of the alternating voltage (V ac) applied to detect the electrostatic force during the KFM measurements gave a better potential profile of the heterostructures. The spatial resolution of the present KFM was investigated by measuring the InAlAs/InGaAs layered structures with various thicknesses. The minimum thickness of the InAlAs layer distinguished by the KFM was 40 nm.