5,6,11,12-tetraphenylnaphthacene (rubrene) is fabricated by spin coating technique on n type GaAs (100) substrate. The current-voltage (I-V) characteristics of Al/rubrene/n-GaAs (100) Schottky diode have been measured in the temperature range of 100-300 K. The experimental values of saturation current (I0), ideality factor (n) and barrier height (ΦB) are calculated as 2.749 pA, 6.051 and 0.297 eV at 100 K and 57.54 pA, 1.918 and 0.870 eV at 300 K, respectively. The values of series resistance (RS) are calculated using Cheung functions at all temperatures. The RS values are found as 1276.4 Ω and 119.7 Ω for 100 K and 300 K, respectively. It is found that barrier heights increased while ideality factors and series resistances decrease with the increasing temperature.