NANOMETER-SCALE IMAGING OF POTENTIAL PROFILES IN OPTICALLY-EXCITED N-I-P-I HETEROSTRUCTURE USING KELVIN PROBE FORCE MICROSCOPY

We report on measurements of the potential profile of a GaAs/AlCaAs n-i-p-i multiple quantum well structure using a scanning Kelvin probe force microscope (KFM). Using this novel technique we directly measure with meV precision and sub-100 nm spatial resolution the potential difference between n-i-p-i layers with and without external optical excitation, The measured potential profiles, which have not been directly imaged previously, agree well with potential profiles calculated for optically excited n-i-p-i structures, but modified by band bending effects at the surface. (C) 1995 American Institute of Physics.