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Proceedings Paper

Tailoring of GaAs/GaAsSb core-shell structured nanowires for IR photodetector applications
Author(s): Pavan Kumar Kasanaboina; Sai K. Ojha; Shifat Us Sami; Lewis Reynolds; Yang Liu; Shanthi Iyer
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Paper Abstract

Ga assisted GaAs/GaAsSb core-shell structured nanowires were successfully grown on chemically etched p-type Si(111) substrate by molecular beam epitaxy (MBE). The morphology, structural and optical properties of the nanowires are found to be strongly influenced by the shell growth temperature and Sb% in the nanowires. The nanowires exhibit planar defects like twins and stacking faults, with more stacking faults and micro-twins found at the top section. Optical characteristics of the nanowires as measured by 4K photoluminescence (PL) exhibit a red shift to 1.2 eV with increasing Sb incorporation up to 12%. The Raman spectra of reference GaAs nanowires show TO and LO modes representative of the zinc blende structure at 291 cm-1 and 267.8 cm-1, respectively. Red shifts of both modes in conjunction with corresponding asymmetrical peak broadening observed in X-ray diffraction with increasing Sb incorporation are attributed to enhanced strain and disorder within the nanostructures. Nanowires of similar Sb composition but grown at different shell temperatures reveal straight nanowires with better microstructural and optical quality when grown at higher growth temperatures. The presence of GaAs passivation layer significantly enhanced the PL intensity such that PL was observed even at room temperature.

Paper Details

Date Published: 27 February 2015
PDF: 9 pages
Proc. SPIE 9373, Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XII, 937307 (27 February 2015); doi: 10.1117/12.2080572
Show Author Affiliations
Pavan Kumar Kasanaboina, North Carolina A&T State Univ. (United States)
Sai K. Ojha, North Carolina A&T State Univ. (United States)
Shifat Us Sami, North Carolina A&T State Univ. (United States)
Lewis Reynolds, North Carolina State Univ. (United States)
Yang Liu, North Carolina State Univ. (United States)
Shanthi Iyer, North Carolina A&T State Univ. (United States)


Published in SPIE Proceedings Vol. 9373:
Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XII
Diana L. Huffaker; Holger Eisele, Editor(s)

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