Scanning Tunnelling Microscope as known as S.T.M is a ultimate microscope that has the power to view individual atoms . Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer won the Nobel Prize in Physics in 1986. The microscope is based on the concept of quantum tunneling.When a conducting tip is brought very near to the surface to be examined, a bias (voltage difference) applied between the two can allow electrons to tunnel through the vacuum between them. The resulting tunneling current is a function of tip position, applied voltage, and the local density of states of the sample.[4] Information is acquired by monitoring the current as the tip's position scans across the surface, and is usually displayed in image form. STM can be a challenging technique, as it requires extremely clean and stable surfaces, sharp tips, excellent vibration control, and sophisticated electronics, but nonetheless many hobbyists have built their own scanning tunneling microscope. So it was hard to use a STM because it requires absolute control of the mechanism.
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