We present the first experimental comparisons of growth of Ga-doped ZnO (GZO) thin films through metalorganic chemical vapor deposition (MOCVD) using Triethylgallium (TEG) and Trimethylgallium (TMG) as dopant sources with qualified opt-electrical properties. Interestingly, we found the GZO films growth by using TEG source exhibited the preferred orientation of (100) and (110) planes which (100) plane is the dominant orientation as well as the formation of pyramidal texture on the film surface compared to the one using TMG source that is highly (002)-orientated ZnO films and formation of planar structure. Additionally, the total C incorporation into GZO films prepared by TEG is slightly lower than that of using TMG source, indicating the formation of stable C2H4 species during reaction when using TEG source can reduce the C incorporation of GZO films compared to the less stable CH3 species by using TMG source. It also found that the doping efficiency by using TEG as a dopant source was much lower than that of using TMG source due to the different thermal decomposition between two sources. These results indicate clearly that the Ga dopant source is crucial to determine the morphology, structure, carbon incorporation as well as the doping efficiency of GZO films that can motivate further research in this field by using various materials.