Influence of the growth temperature on the composition distribution at sub-nm scale of InAlAsSb for solar cells

• Published in: Journal of alloys and compounds Vol. 763; pp. 1005 - 1011
• Main Authors: Hernández-Saz, J., Herrera, M., Pizarro, J., Galindo, P.L., Gonzalez, M., Abell, J., Walters, R.J., Molina, S.I., Duguay, S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30-09-2018; Elsevier BV; Elsevier
• Subjects: Atom probe tomography; Atoms & subatomic particles; Composition; Composition fluctuations; Engineering Sciences; Growth temperature; InAlAsSb; Materials; Micro and nanotechnologies; Microelectronics; Nanocharacterization; Optoelectronics; Periodic variations; Photovoltaic cells; Semiconductors; Solar cells; Tomography; Growth temperature; Semiconductors; Nanocharacterization; Composition fluctuations; Atom probe tomography; InAlAsSb
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.05.333

The composition distribution of In0.16Al0.34As0.41Sb0.09 layers grown at different temperatures with applications in solar cells have been analysed by atom probe tomography. Our results clearly show non-random distributions in both In and Sb in layers grown at 325 °C and 475 °C. The composition fluctuations consist on smooth variations, with a statistically significant periodicity of 10 nm for In and for Sb in the material grown at 475 °C. The amplitude of the composition variations is larger for the layer grown at higher temperature, reaching values as high as 27% In. 3D In-rich regions as small as 1–3 nm have been visualized in both structures, which is a remarkable finding. Our results clearly show a strong influence of the growth temperature in the composition distribution of the InAlAsSb alloy, what explains its previously observed optoelectronic properties.
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•The epitaxial growth of the novel semiconductor InAlAsSb leads to inhomogeneity.•In-rich regions with nucleus as small as of 1–3 nm are found by atom probe tomography.•The magnitude of the compositions fluctuations in enhanced with growth temperature.•Detailed 3D compositional information explains previous photoluminescence properties.