Surface potential measurement of self-assembled InAs dots by scanning Maxwell stress microscopy

We have imaged surface potential of InAs self-assembled quantum dots on GaAs (0 0 1) surface by scanning Maxwell stress microscopy. Simultaneously obtained constant tip–sample capacitance image and surface potential image were compared with atomic force microscope (AFM) image, and was found that the surface potential on large dots of about 100-nm diameter is View the MathML source which is 30–40 mV lower than that on regular size dots. This result well coincides with previously reported Schottky barrier heights which were estimated from current versus voltage measurements with the same type of samples using conductive probe AFM.