STM stands for Scanning Tunneling Microscopy. It is another form of scanning probe microscopy that relies on the quantum mechanical phenomenon of quantum tunneling. In STM, a conductive tip is brought very close to the surface of a conductive or semiconductive sample. When a voltage is applied, electrons tunnel between the tip and the sample, creating a tunneling current. This current is highly sensitive to the distance between the tip and the sample, allowing for atomic-scale resolution.
