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Localized thermal spike driven morphology and electronic structure transformation in swift heavy ion irradiated TiO 2 nanorods.

Authors :
Dey S
Chakravorty A
Mishra SB
Khatun N
Hazra A
Nanda BRK
Sudakar C
Kabiraj D
Roy SC
Source :
Nanoscale advances [Nanoscale Adv] 2021 Nov 15; Vol. 4 (1), pp. 241-249. Date of Electronic Publication: 2021 Nov 15 (Print Publication: 2021).
Publication Year :
2021

Abstract

Irradiation of materials by high energy (∼MeV) ions causes intense electronic excitations through inelastic transfer of energy that significantly modifies physicochemical properties. We report the effect of 100 MeV Ag ion irradiation and resultant localized (∼few nm) thermal spike on vertically oriented TiO <subscript>2</subscript> nanorods (∼100 nm width) towards tailoring their structural and electronic properties. Rapid quenching of the thermal spike induced molten state within ∼0.5 picosecond results in a distortion in the crystalline structure that increases with increasing fluences (ions per cm <superscript>2</superscript> ). Microstructural investigations reveal ion track formation along with a corrugated surface of the nanorods. The thermal spike simulation validates the experimental observation of the ion track dimension (∼10 nm diameter) and melting of the nanorods. The optical absorption study shows direct bandgap values of 3.11 eV (pristine) and 3.23 eV (5 × 10 <superscript>12</superscript> ions per cm <superscript>2</superscript> ) and an indirect bandgap value of 3.10 eV for the highest fluence (5 × 10 <superscript>13</superscript> ions per cm <superscript>2</superscript> ). First principles electronic structure calculations corroborate the direct-to-indirect transition that is attributed to the structural distortion at the highest fluence. This work presents a unique technique to selectively tune the properties of nanorods for versatile applications.<br />Competing Interests: There are no conflicts to declare.<br /> (This journal is © The Royal Society of Chemistry.)

Details

Language :
English
ISSN :
2516-0230
Volume :
4
Issue :
1
Database :
MEDLINE
Journal :
Nanoscale advances
Publication Type :
Academic Journal
Accession number :
36132944
Full Text :
https://doi.org/10.1039/d1na00666e