Room temperature Ultraviolet B emission from InAlGaN films synthesized by plasma-assisted molecular beam epitaxy

Abstract

Thin films of the wide bandgap quaternary semiconductor InxAlyGa(1−x−y)N with low In (x = 0.01–0.05) and high Al composition (y = 0.40–0.49) were synthesized on GaN templates by plasma-assisted molecular beam epitaxy. High-resolution X-ray diffraction was used to correlate the strain accommodation of the films to composition. Room temperature ultraviolet B (280 nm–320 nm) photoluminescence intensity increased with increasing In composition, while the Stokes shift remained relatively constant. The data suggest a competition between radiative and non-radiative recombination occurs for carriers, respectively, localized at centers produced by In incorporation and at dislocations produced by strain relaxation.

UVB-emitting InAlGaN multiple quantum well synthesized using plasma-assisted molecular beam epitaxy

“…1 (a-c) compares its (015) X-ray diffraction (XRD) reciprocal space map (RSM) with those from the In 0.05 Al 0.47 Ga 0.48 N and Al 0.5 Ga 0.5 N reference samples. 22 Fig. 1 (a) shows the 0 th order peak of the MQW, which represents the average composition of the structure.…”

“…[17][18][19][20] Spectroscopic ellipsometry was used to estimate the dielectric functions of the reference samples and the MQW using the methodology described in previous reports. [21][22][23] The refractive index n and the absorption coefficient α were derived from the real and imaginary parts of the dielectric function ε r ( ω) and ε i ( ω). The bandgap energy E A is obtained by linearly extrapolating the function α 2 ( ω) to zero, as shown in Fig.…”