puolijohdevenymäanturit

Puolijohdeveny refers to a semiconductor device that utilizes a phenomenon known as a tunnel diode effect. Unlike conventional diodes which rely on the p-n junction to control current flow, a tunnel diode exhibits a negative differential resistance region. This means that as the voltage across the diode increases, the current initially decreases before starting to increase again. This unique characteristic is a result of quantum mechanical tunneling.

The fabrication of a tunnel diode involves creating a highly doped p-n junction. The extreme doping levels lead to a very thin depletion region, allowing electrons to tunnel directly from the conduction band of one region to the valence band of the other, bypassing the usual diffusion and drift mechanisms. This tunneling current is sensitive to the applied voltage.

At low forward bias voltages, the tunneling current is significant. However, as the voltage increases, the energy levels become misaligned, reducing the probability of tunneling and causing the current to drop. This is the negative resistance region. Beyond this point, as the voltage continues to rise, the conventional diode current starts to dominate, and the current increases with voltage again.

Tunnel diodes have found applications in high-frequency circuits due to their fast switching speeds, such as in oscillators, amplifiers, and high-speed switching circuits. Their negative differential resistance property makes them suitable for creating regenerative circuits where positive feedback can be easily implemented. However, their applications are somewhat limited by their low power handling capability and voltage sensitivity.