Scanning Probe Microscopy (SPM) instruments use a physical probe to scan and image the surface of a sample. The resolution of the microscope is not limited by diffraction, but only by the size of the probe-sample interaction volume, which can be as small as few angstroms. Unlike electron microscopy the specimen does not require vacuum and can be observed in air at standard conditions though vacuum and cryogenic temperatures are needed to achieve the highest resolution which can be a few picometers. This technique can measure 3D surface topography (x, y, and z dimensions), roughness, hardness, elasticity modulus, electrical properties, etc