Quantum Dot Microscope Can Measure Electric Surface Potentials of Single Atoms

A new scanning quantum dot microscopy method can measure the electric potential of a sample at atomic accuracy. It was developed by a team from Forschungszentrum Jülich, working with researchers from two other institutions. The new technique has potential application for chip manufacturing and the characterization of biomolecules. A quantum dot was attached to the tip of an atomic force microscope (AFM) to serve as a noncontact scanning probe. The quantum dot was so small that individual electrons from the tip of the AFM could be attached to it in a controlled manner. The quantum dot sensor and the joint electrostatic screening by tip and surface enabled quantitative surface potential imaging across all length scales down to...