Theory of dielectric relaxation in blocking contact MIM structures

Abstract

Metal-insulator or metal-amorphous semiconductor blocking contacts are important because of their potential solar cell applications.1, 2 However, these structures are still not well understood even for crystalline materials,3 while the case of amorphous material is even more uncertain and poorly understood. In most cases, only steady state characteristics of these structures are studied. This can provide limited information. Characteristics before the current becomes constant can provide information on a wider scale, and thus assumptions on metal-insulator structure can be judged more critically. The theory of dielectric relaxation for MIM structures was first formulated by Simmons and Taylor.4 As recently pointed out by us,5 this theory can explain the experimental results only qualitatively. Thus the correctness of the assumptions of the theory and the conclusions drawn from it are doubtful. We feel that it is still necessary to know the charge conduction mechanism in such structures. The object of the present paper is to discuss the theory of isothermal dielectric relaxation in blocking contact metal-insula tor-metal structures considering various possible assumptions.