Influence of Highly Efficient Carbon Doping on AlxGa1− xAs Layers with Different Al Compositions (x) Grown by MOVPE
Date
27.06.2023Metadata
Show full item recordAbstract
Carbon (C)-doped aluminum gallium arsenide (
AlxGa1−xAs) epitaxial layers with different aluminum (Al) concentrations
have been grown on gallium arsenide (GaAs) substrates by metalorganic vapor phase epitaxy (MOVPE) technique. The
impact of varying carbon tetrabromide (
CBr4) flow rates on the electrical properties of AlxGa1−
xAs materials with different Al
compositions has been investigated. High-resolution x-ray diffraction (HRXRD) measurement and a Hall effect measurement
system have been used to determine the Al compositions and to evaluate the electrical properties. It has been found that the
carrier density increases and the mobility decreases by increasing the flow rate of CBr4
and changing Al compositions up
to a certain point. In contrast, at higher Al compositions, a decrease in carrier density and an increase in mobility have been
observed with increasing CBr4
flow rate. Since these observed trends require to be analyzed in more detail, x-ray photoelectron
spectroscopy (XPS) has been used to analyze the elements in the structure. From the XPS results, it has been shown
that the atomic concentration of the arsenic in the structure decreased with the increase in CBr4
flow rates. In addition, it has
been shown that the Al composition in the AlxGa1−
xAs material obtained from the XRD results increases with the increase
in the atomic concentration of the arsenic. Accordingly, a linear increase in carrier concentration is shown with increasing
Al composition. This increase is explained by the effect of the Al–C bond content on the electrical properties of AlxGa1−
xAs.