Defect-engineered optical bandgap in self-assembled TiO{sub 2} nanorods on Si pyramids

Journal Article · Mon Jan 04 00:00:00 EST 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4939662· OSTI ID:22489237

Saini, C. P.; Barman, A.; Satpati, B.; Bhattacharyya, S. R. ^[1]; Kanjilal, D. ^[2]

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1. Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)
2. Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

Transformation of self-assembled crystalline TiO{sub 2} nanorods to amorphous layer, and the corresponding impact on optical-bandgap (E{sub g}) on Si pyramids are investigated by irradiating with 50 keV Ar{sup +}-ions. Initially, E{sub g} is found to be reduced from 3.23 to 2.94 eV up to a fluence of 1 × 10{sup 16} ions/cm{sup 2}, and discussed in terms of the rise in oxygen vacancies (V{sub O}). However, a sudden increase in E{sub g} to 3.38 eV is detected at a fluence of 1 × 10{sup 17} ions/cm{sup 2} through evolution of voids by over-saturating V{sub O}, manifesting the appearance of degenerate states by shifting the Fermi level above the conduction band minimum via Burstein-Moss effect.

• OSTI ID: 22489237
• Journal Information: Applied Physics Letters, Vol. 108, Issue 1; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARGON IONS
FERMI LEVEL
KEV RANGE 10-100
LAYERS
NANOSTRUCTURES
OXYGEN
TITANIUM OXIDES
VACANCIES
VOIDS