ELECTRICAL-PROPERTIES OF P-NIO N-ZNO 2-PHASE MIXTURES/

Thermopower and electrical conductivity of the two-phase mixtures of s emiconducting oxides having different types of majority charge carrier s, (1-x)NiO-xZnO system, were measured as functions of composition (0 less than or equal to x less than or equal to 1), topography of second phase (morphology, thickness of intergranular phase) and temperature (25 less than or equal to T/degrees C less than or equal to 1050). The rmopower varies from p- to n-type with respect to composition and temp erature. Especially, p-n transition temperature depends on the second phase volume fraction and/or thickness of intergranular phase. The var iations of electrical properties of p-n mixtures with respect to compo sition, temperature and microstructure are discussed by considering th e existence of highly resistive charge depletion region along the p-n heterojunctions.