Electrical characterization of InGaAs/InP quantum wells by scanning capacitance microscopy

In this work, cross-sectional scanning capacitance microscopy (SCM) is used to investigate InGaAs/InP quantum wells. It is demonstrated that SCM is indeed capable of detecting the electrons in the quantum wells and that the SCM signal shows a systematic trend for the different wells. Clear dips in the dC/dV signal are observed at the InGaAs quantum wells and imply carrier densities higher than the surrounding barriers. It is also shown that the depletion regions in the barriers adjacent to the wells can be resolved. The results show that geometric tip-averaging effects significantly influence the imaging of electrons in quantum wells and limit the lateral resolution.