Determination of the direct to indirect bandgap transition composition in AlxIn1−xP

Abstract

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Band Alignment at GaxIn1–xP/AlyIn1–yP Alloy Interfaces from Hybrid Density Functional Theory Calculations

“…The direct–indirect crossover is calculated to occur for intermediate stoichiometries, i.e., for . This is in between the value determined by photoluminescence spectroscopy, [ 14 ] and previous calculations that obtained . [ 15 ] Again, the valence band offset for the binary end points can be compared with previous theory based on the alignment with respect to the core levels.…”

“…[ 12 ] According to photoluminescence data, [ 13 ] the Ga content of at the direct–indirect bandgap crossover is at about x = 0.71. Measurements for indicate the direct–indirect crossover for y = 0.41, [ 14 ] whereas recent density functional calculations place it at y = 0.48. [ 15 ]…”

GaInP/AlInP(001) Interfaces from Density Functional Theory

“…[ 25 ] The direct–indirect bandgap crossover of Ga x In 1− x P and Al y In 1− y P occurs for In‐poor and In‐rich stoichiometries, respectively. [ 7,26–28 ] The measured bandgaps of randomly ordering Ga 0.5 In 0.5 P and Al 0.5 In 0.5 P alloys amount to about 1.9 [ 29,30 ] and 2.3 eV. [ 31 ] In Figure 1 , we show the band structures of CuPt‐type ordered GaInP and AlInP crystals, calculated at the respective equilibrium lattice constants of 5.71 and 5.70 Å obtained from structural relaxation.…”

Quantitative order‐parameter measurement in lattice‐mismatched AlInP using precession electron diffraction

“…Such an approach has been proposed for improving the efficiency of red and amber LEDs through the use of direct bandgap Al x In 1– x P (AlInP) alloys as the light emitter 4 . Al x In 1– x P (AlInP) has an indirect bandgap at lattice‐matched compositions (), but undergoes a transition to a direct gap with 5 . Lattice mismatch to GaAs is introduced at these compositions, so metamorphic growth is used to form device‐quality AlInP active layers.…”

“…4 Al x In 1-x P (AlInP) has an indirect bandgap at lattice-matched compositions (𝑥 Al ≈ 0.5), but undergoes a transition to a direct gap with 𝑥 Al < 0.4. 5 Lattice mismatch to GaAs is introduced at these compositions, so metamorphic growth is used to form devicequality AlInP active layers. Little information is available on the strength of ordering in AlInP, particularly in such off-stochiometric, metamorphic films.…”