Depositions were carried out in a Picosun R-200 atomic layer deposition tool without a load lock chamber and a operating pressure of 6 hPa. An ICP plasma was generated within a quartz tube surrounded by a cylindrical RF coil with the substrate holder located approximately 70 cm downstream from the plasma source. ALD of GaN was done within the temperature range 160-350 ºC on 2×2 cm Si (100) with native oxide using alternative pulses of TEG and NH3/Ar plasma, separated by N2 purges, as precursors. TEG was kept in a stainless-steel bubbler at room temperature. N2 (99.999 %) was used as a purge gas for the whole deposition system and as a carrier gas for triethylgallium precursor delivery into the reaction chamber, while Ar (99.9997 %) was used as the carrier gas for H2 (99.999 %) and NH3 (99.999990 %) precursor delivery. The N2, Ar, NH3, and H2 gases were further purified by getter filters to further remove moisture. Si (100) substrates were loaded and kept at deposition temperature for at least 120 min before the growth process was started. To minimize the negative impact of atmospheric exposure during the sample loading process and to remove any water vapor adsorbed from the reactor walls upon sample loading, a 2 min NH3/Ar (50/100 sccm) 2800 W and 2 min N2/Ar (50/100 sccm) 2800 W plasma cleaning procejure was employed. This plasma pre-treatment aims to reduce oxide and carbon residuals as previously reported. To study how to enhance the ethyl ligand removal from the surface, an additional pulse was added between the TEG and NH3/Ar plasma to form an ABC-type pulsed ALD process, similar to a previous study on ALD of aluminium nitride . For each set of experiments, the A-pulse was 0.3 s TEG exposure and the C-pulse was a 30 s NH3 plasma exposure using a mixture of 50 sccm NH3 and 100 sccm Ar with 2800 W plasma power.