Practice question

Scanning Tunneling Microscopy achieves atomic resolution by exploiting quantum tunneling. A sharp conductive tip biased at millivolts approaches conducting sample within one nanometer, allowing electrons to tunnel across gap, creating measurable current that exponentially depends on distance. Scanning maintains constant current, producing topographic map revealing individual atoms and electronic states. Unlike SEM or TEM using electron lenses, or AFM sensing forces, STM requires conductive surfaces and operates via tunneling current, enabling visualization of graphite lattices, metal surfaces, and self-assembled monolayers with unprecedented atomic-scale precision in materials and structural biology research.