PN JUNCTIONS IN MIXED IONIC ELECTRONIC CONDUCTORS INDUCED BY CHEMICALAND ELECTRICAL POTENTIAL GRADIENTS

Non uniform charged defect distribution can arise in single phase, a p riori uniform, mixed ionic-electronic conductors (MIECs) subject to gr adients in the chemical potential and/or to applied voltages. The elec tronic defects may form graded n, graded p regions and pn or pin junct ions. Yet this need not require the existence of a space charge. In th e case of zero space charge the I-V characteristics of the pn junction s are very different from those of normal pn diodes. The electronic de fect distribution for the main types of MIECs are discussed and the ef fect of chemical potential gradient and applied voltage in the steady state are demonstrated. Criteria for neglecting the space charge are g iven.