Impact of disorder on the optoelectronic properties of GaN${}_y$As${}_{1-x-y}$Bi${}_x$ alloys and heterostructures

Abstract

We perform a systematic theoretical analysis of the nature and importance of alloy disorder effects on the electronic and optical properties of GaN${}_y$As${}_{1-x-y}$Bi${}_x$ alloys and quantum wells (QWs), using large-scale atomistic supercell electronic structure calculations based on the tight-binding method. Using ordered alloy supercell calculations we also derive and parametrise an extended basis 14-band \textbf{k}$\cdot$\textbf{p} Hamiltonian for GaN${}_y$As${}_{1-x-y}$Bi${}_x$. Comparison of the results of these models highlights the role played by short-range alloy disorder -- associated with substitutional nitrogen (N) and bismuth (Bi) incorporation -- in determining the details of the electronic and optical properties. Systematic analysis of large alloy supercells reveals that the respective impact of N and Bi on the band structure remain largely independent, a robust conclusion we find to be valid even in the presence of significant alloy disorder where N and Bi atoms share common Ga nearest neighbours. Our calculations reveal that N- (Bi-) related alloy disorder strongly influences the conduction (valence) band edge states, leading in QWs to strong carrier localisation, as well as inhomogeneous broadening and modification of the conventional selection rules for optical transitions. Our analysis provides detailed insight into key properties and trends in this unusual material system, and enables quantitative evaluation of the potential of GaN${}_y$As${}_{1-x-y}$Bi${}_x$ alloys for applications in photonic and photovoltaic devices.

arXiv comment29 pages, 11 figures

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Cited by in corpus (8)

• Electronic structure evolution in dilute carbide Ge${}_{1-x}$C${}_x$ alloys and implications for device applications
• Electronic and optical properties of Si${}_x$Ge${}_{1-x-y}$Sn${}_y$ alloys lattice-matched to Ge
• Impact of stoichiometry and strain on Ge${}_{1-x}$Sn${}_x$ alloys from first principles calculations
• Towards low-loss telecom-wavelength photonic devices by designing GaBi${}_x$As${}_{1-x}$/GaAs core$-$shell nanowires
• Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires
• Influence of sample momentum space features on scanning tunnelling microscope measurements
• Nanowire design by deep learning for energy efficient photonic technologies
• Atomistic tight binding study of quantum confined Stark effect in GaBi${}_x$As${}_{1-x}$/GaAs quantum wells