Scanning near-field optical microscopy of AlGaN epitaxial layers

• Scanning near-field PL spectroscopy was applied to study spatial variations of the emission spectra of AlGaN epilayers with AlN molar fractions between 0.3 and 0.7. Experiments were performed at 300 K with 100 nm spatial resolution. In general, photoluminescence spectra were found to be highly uniform with the peak energy deviation of 2 to 6 meV for different alloy compositions. In the 30% and 42% Al layers, a slightly lower Al content and a higher point defect concentration at the boundaries of growth domains were detected. These features were attributed to the higher mobility of Ga adatoms during growth. The inhomogeneous broadening beyond the random alloy distribution was found negligible for the 30% and 42% Al samples, and about 40 - 50 meV for the layers with a larger Al content.

Subject headings

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Keyword

AlGaN

Scanning near-field optical microscopy

SNOM

NSOM

photoluminescence

localization

Publication and Content Type

ref (subject category)

kon (subject category)