Abstract

We report on the electronic, structural, and optical properties of epitaxial GaSbBi films with varying Bi-concentration (up to 7%Bi) grown on semi-insulating GaAs(100) substrates. The 1 µm thick GaSbBi epilayers exhibit fully relaxed narrow X-ray diffraction peaks and smooth surface morphology comparable to that of high-quality GaSb epilayers on GaAs. Low temperature photoluminescence spectra exhibit band gap shrinkage consistent with Bi alloying. Electrical Hall measurements indicate reduction of hole concentration and no change in the hole mobilities with increasing Bi content for the nominally undoped GaSbBi alloy. The residual hole concentration reduces from 1018 cm⁻³ level for a reference GaSb sample, to low 1017 cm⁻³ level with increasing Bi content. Hole mobility values of around 300 cm2/Vs are observed independent of the Bi content. These dependencies are attributed to the Bi surfactant effect and Bi-induced defect formation.

Abstract

We report on the electronic, structural, and optical properties of epitaxial GaSbBi films with varying Bi-concentration (up to 7%Bi) grown on semi-insulating GaAs(100) substrates. The 1 µm thick GaSbBi epilayers exhibit fully relaxed narrow X-ray diffraction peaks and smooth surface morphology comparable to that of high-quality GaSb epilayers on GaAs. Low temperature photoluminescence spectra exhibit band gap shrinkage consistent with Bi alloying. Electrical Hall measurements indicate reduction of hole concentration and no change in the hole mobilities with increasing Bi content for the nominally undoped GaSbBi alloy. The residual hole concentration reduces from 1018 cm⁻³ level for a reference GaSb sample, to low 1017 cm⁻³ level with increasing Bi content. Hole mobility values of around 300 cm2/Vs are observed independent of the Bi content. These dependencies are attributed to the Bi surfactant effect and Bi-induced defect formation.

Abstract

We report on the electronic, structural, and optical properties of epitaxial GaSbBi films with varying Bi-concentration (up to 7%Bi) grown on semi-insulating GaAs(100) substrates. The 1 µm thick GaSbBi epilayers exhibit fully relaxed narrow X-ray diffraction peaks and smooth surface morphology comparable to that of high-quality GaSb epilayers on GaAs. Low temperature photoluminescence spectra exhibit band gap shrinkage consistent with Bi alloying. Electrical Hall measurements indicate reduction of hole concentration and no change in the hole mobilities with increasing Bi content for the nominally undoped GaSbBi alloy. The residual hole concentration reduces from 1018 cm⁻³ level for a reference GaSb sample, to low 1017 cm⁻³ level with increasing Bi content. Hole mobility values of around 300 cm2/Vs are observed independent of the Bi content. These dependencies are attributed to the Bi surfactant effect and Bi-induced defect formation.

Abstract

We report on the electronic, structural, and optical properties of epitaxial GaSbBi films with varying Bi-concentration (up to 7%Bi) grown on semi-insulating GaAs(100) substrates. The 1 µm thick GaSbBi epilayers exhibit fully relaxed narrow X-ray diffraction peaks and smooth surface morphology comparable to that of high-quality GaSb epilayers on GaAs. Low temperature photoluminescence spectra exhibit band gap shrinkage consistent with Bi alloying. Electrical Hall measurements indicate reduction of hole concentration and no change in the hole mobilities with increasing Bi content for the nominally undoped GaSbBi alloy. The residual hole concentration reduces from 1018 cm⁻³ level for a reference GaSb sample, to low 1017 cm⁻³ level with increasing Bi content. Hole mobility values of around 300 cm2/Vs are observed independent of the Bi content. These dependencies are attributed to the Bi surfactant effect and Bi-induced defect formation.