Syntheses, X-ray structures and CVD studies of diorganoalkoxogallanes

Structural studies by X-ray crystallography have been carried out for a range of diorganoalkoxogallanes incorporating donor-functionalized ligands. The compounds [Et2Ga(μ-OR)]2 (1, R = CH2CH2NMe2; 2, R = CH(CH3)CH2NMe2; 3, C(CH3)2CH2OMe; 4, R = CH(CH2NMe2)2) adopt dimeric structures with a planar Ga2O2 ring, and each gallium atom is coordinated in a distorted trigonal bipyramidal geometry. Low pressure chemical vapor deposition (CVD) of 2 and 4 resulted in the formation of oxygen deficient gallium oxide thin films on glass. However, the reaction of Et3Ga and ROH (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH(CH2NMe2)2) in toluene under aerosol assisted (AA)CVD conditions afforded stoichiometric Ga2O3 thin films on glass. This CVD technique offers a rapid, convenient route to Ga2O3, which involves the in situ formation of diethylalkoxogallanes, of the type [Et2Ga(μ-OR)]2, the structures of which are described in this paper. The gallium oxide films were deposited at 450 °C and analyzed by scanning electron microscopy (SEM), X-ray powder diffraction, wavelength dispersive analysis of X-rays (WDX), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.

Graphical abstractStructural studies of the diethylalkoxogallanes, [Et2Ga(μ-OR)]2 (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH(CH2NMe2)2) incorporating donor-functionalized ligands have shown that these compounds adopt dimeric structures. Thin films of Ga2O3 have been deposited on glass by low pressure CVD using some of the compounds or via aerosol assisted CVD from the reaction of Et3Ga and ROH (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH(CH2NMe2)2) in toluene.Figure optionsDownload full-size imageDownload as PowerPoint slide