A study of the mechanism of the reaction of trimethylgallium with hydrogenselenide

A study of the pre-deposition room temperature gas-phase reactions involved in the growth of Ga2Se3 (and/or GaSe) using trimethylgallium (GaMe3) and h ydrogen selenide (H2Se) was undertaken, using a simple mass spectrometric s ampling system on a conventional atmospheric pressure MOCVD reactor. The ex perimental studies were complemented by theoretical quantum chemical calcul ations which were used to predict the reaction thermochemistry and kinetics of the proposed reaction scheme. We have shown that the gas phase reaction of the GaMe3-H2Se mixture can be described by a simple reaction mechanism with no need for the participation of a stable Lewis acid-base adduct, alth ough a transient adduct type species may be involved. The effect of the roo m temperature reaction of GaMe3 with H2Se on the growth mechanism of Ga2Se3 /GaSe and its role in determining epilayer morphology and microstructure ar e also discussed.