Gallium oxide, deposition

The isomorphism between alumina and gallia renders a comparative study difficult, but the observed differences in heats of adsorption for the two samples show that the nature of the interaction between active phase and support, and thus the dispersion, are different, a situation for which the preparation method should be responsible. Indeed, in aqueous solution the gallium oxide deposition occurs preferentially on the strongest OH... 

The XRD patterns were the same for the supported samples as for the alumina support. This showed that gallium oxide was deposited in an amorphous phase but did not allow to differentiate the quality of the dispersiom The better dispersion of the sol-gel sample in comparison with the impregnated sample was confirmed by TEM and XPS measurements. 

Fu, L. Lever, P. Tan, H. H. Jagadish, C Reece, P. Gal, M. (2002). Suppression of interdiffusion in GaAs/AlGaAs quantum-well structure capped with dielectric films by deposition of gallium oxide, Appl. Phys. Lett., Vol. 82, 3579-3583, ISSN... 

The catalytic materials of the series V-Ga-O have been prepared by depositing VO, on Ga203 [2] Vanadiiun(V)oxide was dissolved at 353 K in oxalic acid. The gallium oxide was added to the solution after stirring for 30 min the water was evaporated at 353 K. For the preparation of V-Mg oxide with MgA atomic ratios of 9/1, 4/1, 1/1 and 1/4, fleshly prepared Mg(OH)2 was added to a aqueous solution of NH4VO3 (Merck, p.a) followed by water evaporation [3]. Drying and calcination of the samples were performed as described above. 

Catalysts based on other metals, such as gallium and vanadium oxides, can be also employed in DH processes [8, 9]. For example, silica-supported gallium oxide catalyst has been found to be moderately active, but quite selective in propane dehydrogenation (up to 80%) and results in much less coking, 1/10 of that using a silica-supported chromium oxide [8], There is an extensive research aimed to find new DH catalysts that will perform well at moderate temperatures, suffer less from coke deposition and maintain catalytic activity for long periods of time without regeneration. 

New developments relating to the manufacture of thin film transistors (TFT) are being reported from Japan where the Tokyo Institute of Technology has developed a flexible, transparent device on a PETP substrate. This TFT comprises an amorphous oxide semiconductor, which serves as the active layer, and which is made from indium, gallium and zinc oxide deposited by laser ablation to a thickness of 30-60 nm. The TFT, with its transparent electrodes and circuitry, is manufactured in a vacuum at a temperature of 150 "C or less. Because of this low processing temperature it is possible to use low cost PET film, with a thickness of 200 pm, as a substrate thereby enabling transistors to be manufactured at a relatively low cost. 

Monolayers can be transferred onto many different substrates. Most LB depositions have been perfonned onto hydrophilic substrates, where monolayers are transferred when pulling tire substrate out from tire subphase. Transparent hydrophilic substrates such as glass [18,19] or quartz [20] allow spectra to be recorded in transmission mode. Examples of otlier hydrophilic substrates are aluminium [21, 22, 23 and 24], cliromium [9, 25] or tin [26], all in their oxidized state. The substrate most often used today is silicon wafer. Gold does not establish an oxide layer and is tlierefore used chiefly for reflection studies. Also used are silver [27], gallium arsenide [27, 28] or cadmium telluride wafer [28] following special treatment. 

J. Hu and R.G. Gordon, Atmospheric pressure chemical vapor deposition of gallium doped zinc oxide thin films from diethyl zinc, water, and triethyl gallium, J. Appl. Phys., 72 5381-5392, 1992. 

The drain and source are based on highly conductive gallium doped zinc oxide (GZO), 150 nm thick and patterned by the lift-off technique. These depositions were also carried out at room temperature. 

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