Total Current In Semiconductor — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Total Current in Semiconductor Applicable to intrinsic and extrinsic semiconductors where both charge carriers (electrons and holes) contribute to the net current flow under an applied electric field. Electric current is defined as the rate of flow of net charge through a cross-section. In semiconductors, charge carriers are electrons (negative charge) and holes (positive charge). Under an electric field, electrons move towards the positive terminal (opposite to field) and holes move towards the negative terminal (along field). The conventional current direction for electrons is opposite to their motion (i.e., along the field). The conventional current direction for holes is along their motion (i.e., along the field). Since both conventional currents point in the same direction, the total current is the scalar sum: I = I e + I h. Assumes the semiconductor is not in breakdown. Valid for drift current calculations in steady state. Students often think I e and I h cancel out because electrons and holes move in opposite directions. In reality, their charges are opposite, so their contributions to conventional current add up. Ignoring the hole current contribution in extrinsic n-type semiconductors (minority carriers still exist, though majority dominates).