Current crowding
（重定向自Current crowding effect）
Current crowding (also current crowding effect, or CCE) is a nonhomogenous distribution of current density through a conductor or semiconductor, especially at the vicinity of the contacts and over the PN junctions.
Current crowding is one of the limiting factors of efficiency of light emitting diodes. Materials with low mobility of charge carriers, e.g. Aluminium gallium indium phosphide (AlGaInP), are especially prone to current crowding phenomena. It is a dominant loss mechanism in some LEDs, where the current densities especially around the P-side contacts reach the part of the emission characteristics with lower brightness/current efficiency.