Open AccessHVPE growth of α- and ε-Ga2O3 on patterned sapphire substrates
Author(s) -
В. И. Николаев,
A. I. Pechnikov,
V. V. Nikolaev,
M. P. Scheglov,
A. V. Chikiryaka,
С. И. Степанов,
Oleg Medvedev,
Sevastian Shapenkov,
E. V. Ubyivovk,
O. F. Vyvenko
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1400/5/055049
Subject(s) - sapphire , materials science , epitaxy , transmission electron microscopy , full width at half maximum , substrate (aquarium) , cathodoluminescence , crystallinity , scanning electron microscope , layer (electronics) , phase (matter) , analytical chemistry (journal) , optoelectronics , optics , crystallography , luminescence , composite material , nanotechnology , chemistry , laser , oceanography , physics , organic chemistry , chromatography , geology
Here we report on the growth and characterisation of α- and ε-Ga 2 O 3 epitaxial films produced by halide vapour phase epitaxy (HVPE). The films were deposited on two types of substrate: (0001) plain sapphire substrates and (0001) patterned sapphire substrates with regular cone-like features. In order to guarantee the same growth conditions on plain and patterned sapphire, the two substrates were used simultaneously in the same growth run. After the deposition the samples were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical transmission (OT) spectroscopy, and cathodoluminescence (CL). The growth on plain sapphire substrate produced an 11 μm thick continuous α-Ga 2 O 3 layer. The full width at half maximum (FWHM) of the (0006) XRD rocking curve is 180 arcsec, which indicates good crystallinity of the layer. In contrast, growth on the patterned sapphire substrate resulted in a layer with regular spaced faceted pyramids at the surface. XRD analysis revealed the presence of both α- and ε-phases in Ga 2 O 3 grown on patterned sapphire substrate. The presence of the ε-Ga 2 O 3 phase, which has narrower bandgap, was also confirmed by optical transmission measurements. SEM, TEM, and SEM CL observations revealed that α-Ga 2 O 3 phase forms columnar structures on top of sapphire cone, and ε-Ga 2 O 3 phase fills the valleys between the columns.