Passivation efficacy study of Al 2 O 3 dielectric on self-catalyzed molecular beam epitaxially grown GaAs 1- x Sb x nanowires.

Autor: Parakh M; Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a., Ramaswamy P; Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro NC, 27411, United States of America., Devkota S; Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a., Kuchoor H; Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a., Dawkins K; Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a., Iyer S; Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a.
Jazyk: angličtina
Zdroj: Nanotechnology [Nanotechnology] 2022 May 11; Vol. 33 (31). Date of Electronic Publication: 2022 May 11.
DOI: 10.1088/1361-6528/ac69f8
Abstrakt: This work evaluates the passivation efficacy of thermal atomic layer deposited (ALD) Al 2 O 3 dielectric layer on self-catalyzed GaAs 1- x Sb x nanowires (NWs) grown using molecular beam epitaxy. A detailed assessment of surface chemical composition and optical properties of Al 2 O 3 passivated NWs with and without prior sulfur treatment were studied and compared to as-grown samples using x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature photoluminescence (PL) spectroscopy. The XPS measurements reveal that prior sulfur treatment followed by Al 2 O 3 ALD deposition abates III-V native oxides from the NW surface. However, the degradation in 4K-PL intensity by an order of magnitude observed for NWs with Al 2 O 3 shell layer compared to the as-grown NWs, irrespective of prior sulfur treatment, suggests the formation of defect states at the NW/dielectric interface contributing to non-radiative recombination centers. This is corroborated by the Raman spectral broadening of LO and TO Raman modes, increased background scattering, and redshift observed for Al 2 O 3 deposited NWs relative to the as-grown. Thus, our work seems to indicate the unsuitability of ALD deposited Al 2 O 3 as a passivation layer for GaAsSb NWs.
(© 2022 IOP Publishing Ltd.)
Databáze: MEDLINE
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