what is drift current

Drift current is the electric current, or movement of charge carriers, which is due to the applied electric field in a semiconductor material. When an electric field is applied across a semiconductor material, a current is produced due to the flow of charge carriers. The drift velocity is the average velocity of the charge carriers in the drift current. The drift velocity, and resulting current, is characterized by the mobility. Drift current is caused by the electric force: Charged particles get pushed by an electric field. Electrons, being negatively charged, get pushed in the opposite direction to the electric field, while holes get pushed in the same direction as the electric field, but the resulting conventional current points in the same direction as the electric field in both cases. Drift current is one of the two types of currents responsible for conductivity in a semiconductor, the other being diffusion current. The movement of charge carriers from higher concentration to lower concentration generates diffusion current, which occurs when a semiconductor is doped non-uniformly.