1 research outputs found
Dimensional Dependence of the Optical Absorption Band Edge of TiO<sub>2</sub> Nanotube Arrays beyond the Quantum Effect
Instead
of investigating the quantum effect that influences the
absorption band edge of TiO<sub>2</sub> nanostructures, herein we
report that geometrical parameters can also be utilized to manipulate
the optical band gap of the TiO<sub>2</sub> nanotube arrays. Hexagonal
arrays of TiO<sub>2</sub> nanotubes with an excellent crystalline
quality were fabricated by techniques combining anodic aluminum oxide
templates and atomic layer deposition. Through absorption spectroscopic
analysis we observed that the optical absorption band edge of the
TiO<sub>2</sub> nanotube arrays exhibited a red shift as the diameter
of the nanotube was tuned to be larger and the distance between two
nanotubes became smaller accordingly, while the wall thickness of
the nanotube was kept constant. Subsequent finite-difference time-domain
simulations supported the observation from theoretical aspect and
revealed a large near-field enhancement around the outer space of
the nanotubes for the arrays with densely distributed nanotubes when
the corresponding arrays were exposed to the illuminations. Thus,
this paper provides a new perspective for the shift of the optical
band gap, which is of great significance to the research in photoelectronics