Heterojunctions of solid C70 and crystalline silicon: Rectifying properties and barrier heights

Abstract

Heterojunctions of solid C70 and n- or p-type crystalline Si have been made. Current–voltage measurements show that both C70/n-Si and C70/p-Si contacts are rectifying but their directions of rectification are opposite to each other. Thermal activation measurements at a fixed forward bias show an exponential dependence of current on the reciprocal of temperature, from which we determine the effective barrier height as 0.23 eV for C70/n-Si and 0.27 eV for C70/p-Si. Relative dielectric constant of solid C70 was determined to be 4.96 through the study of high-frequency capacitance–voltage characteristics for Ti/C70/p-Si structures.