4 results for “H. Helava”

AuthorH. Helava1 article

Research ArticleOpen accessIn the author namesPhotoelectrochemical Corrosion of GaN/AlGaN-Based p-n StructuresAlexander Usikov, Heikki Helava, Alexey Nikiforov et al.Direct water photoelectrolysis using III-N materials is a promising way for hydrogen production. GaN/AlGaN based p-n structures were used as working electrodes in a photoelectrochemical process to investigate the material etching (corrosion). The structures were grown on sapphire substrates by chloride Hydride Vapor Phase Epitaxy (HVPE). First, the etching process occurs near vertically via channels associated with defects in the … …American Journal of Applied Sciences, Vol. 13, Issue 7 · 31 Jul 2016 · 7,335 accessesView PDF Cite

Research ArticleOpen accessIn the author namesDEEP TRAPS SPECTRA IN UNDOPED GAN FILMS GROWN BY HYDRIDE VAPOR PHASE EPITAXY UNDER VARIOUS CONDITIONSA. Y. Polyakov, N. B. Smirnov, A. V. Govorkov et al.Decreasing the residual donors density and deep traps spectra densities in undoped GaN films grown by Hydride Vapor Phase Epitaxy (HVPE) is very important for promoting the use of such material in high-voltage/high-power rectifiers, radiation detectors. In this study we studied the effects of changing the growth temperature of undoped HVPE GaN films on these properties. The two groups of … …American Journal of Applied Sciences, Vol. 11, Issue 9 · 30 Sep 2014 · 6,901 accessesView PDF Cite