Micro-sized ZnO rods on SnO 2 coated glass substrate were obtained by spray pyrolysis method. Then a p-type nanorod ZnO layer was deposited on this micro-sized n-ZnO to produce a p-n homojunction. Temperature dependent current–voltage ( I– V) characteristics were measured in the temperature range 150–300 K with a step of 25 K. The current–voltage characteristics exhibit electrical rectification behavior. The zero bias barrier height Φ b 0 increases and ideality factor n decreases with an increase in temperature. The apparent Richardson constant and mean barrier height were found to be 0.062 A cm −2 K −2 and 0.122 eV, respectively in the range 150–300 K. After barrier height inhomogeneities correction, the Richardson constant and the mean barrier height were obtained as 179.05 A cm −2 K −2 and 0.884 eV respectively.