FUNDAMENTAL AND PRACTICAL ASPECTS OF DIFFERENTIAL SCANNING TUNNELING MICROSCOPY

Phase-sensitive techniques can be used to measure differential surface topography in noisy environments, such as those encountered in technological applications. We present a variety of atomic resolution images of the Au(110) (1 x 2), Cu(111), and stepped surfaces recorded in the conventional and differential modes. Reconstruction of the topography from the differential image reveals that, although the technique suppresses most noise, an undesirable amplification of the 1/f component occurs in agreement with theoretical analysis. We demonstrate that such noise can nevertheless be removed with suitable filtering techniques.