Nonlinear Mechanism of I-V Characteristics of MBM Diodes in Low Voltage Region

The current-voltage characteristics of point-contact metal-barrier-metal diodes, the asymmetric nonlinearity of which corresponds to the rectifying property for a radiation field, are studied using a one-dimensional electron tunneling scheme through the barrier between the surfaces of the contacted metals. Anumerical calculation with accuracy higher than the Wentzel-Kramer-Brillouin approximation shows that the barrier asymmetry cannot account for the measured nonlinearity in the low bias voltage region V_b≪φ/e. In this paper, the electron densities of the states of each contact metal are included in the explanation of the rectifying property, and the calculated results agree well qualitatively with the measured nonlinearity of W-Ni, W-Co, and W-Rh diodes.