p-ZnO/n-6H-SiC heterojunction has been fabricated by depositing Al-N co-doped p-type ZnO film on n-6H-SiC by a low-cost sol-gel technique. The junction shows good diode characteristics with a rectification ratio, (I-F/I-R) of about 35 at 4 V. The conduction band offset of the heterojunction has been measured by temperature dependent current-voltage characteristics. By fitting the experimental data, the current transport mechanism is shown to be dominated by the recombination tunneling and drift diffusion at lower and by the space-charge limited current at higher bias voltages. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3608998] All rights reserved.