Molecular beam epitaxy of GaNAs alloys with high As content for potential photoanode applications in hydrogen production
(Color online) X-ray diffraction data for layers grown on sapphire substrates at high (a) and low (b) growth temperatures. RBS/PIXE measurements estimate that the As concentrations in layers are (a) and (b).
SAED pattern from a series of GaNAs samples with increasing As content from 10% to 70% showing crystalline to amorphous transition (a). A typical cross-sectional TEM micrograph of an amorphous film (; ) (b).
(Color online) Energy dependence of the square of the absorption coefficient for layers, grown at different temperatures from to . The As content in the GaNAs films was determined by combined RBS and PIXE measurements.
(Color online) Soft XAS and SXE results for GaNAs samples grown at different temperatures from to .
(Color online) Optical band gap of the films as a function of the overall As content measured by RBS/PIXE. Calculated composition dependence of the band gap of alloys based on the BAC model, virtual crystal approximation and using a single bowing parameter extracted from dilute alloys are also shown. Reported results (Ref. 10) for As-rich GaNAs alloys are also presented.
(Color online) Comparison of the optical absorption data from two samples with comparable composition grown on glass and sapphire.
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