Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography

Hyeong Ho Park, Xin Zhang, Soon Won Lee, Dong Joo Jeong, Sang Moo Lee, Ki Don Kim, Dae Geun Choi, Jun Hyuk Choi, Jihye Lee, Eung Sug Lee, Ho Kwan Kang, Hyung-Ho Park, Ross H. Hill, Jun Ho Jeong

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A direct ultraviolet (UV)-assisted nanoimprinting procedure using photosensitive titanium di-n-butoxide bis(2-ethylhexanoate) is employed in this study for the nanopatterning of anatase titanium dioxide (TiO2) structure. Upon annealing at 400 °C for 1 h, the lateral shrinkage and thickness shrinkage of the TiO2 nanostructure were 39.6% and 52.5%, respectively, which indicated an anisotropic volume loss. During UV irradiation and annealing treatment, the refractive index of UV-irradiated TiO2 film is gradually increased by improvement in the packing density and crystallinity of the film. According to increasing UV exposure time and annealing temperature, the optical band gap (Eg) of UV-irradiated TiO2 film is red-shifted from 3.73 to 3.33 eV due to the formation of lattice defects, vacancies and voids during the photochemical reaction and due to the effect of quantum confinement during annealing treatment. These results suggest that the refractive index and optical Eg of TiO2 nanostructure could be controlled by tuning the UV exposure time and annealing treatment conditions. Nanopatterns of TiO2 fabricated by direct UV-assisted nanoimprint lithography are potential candidates for use in protective coatings for optical mirrors and filters, high-reflectivity mirrors, broadband interference filters and active electro-optical devices where ordered surface nanostructures could be necessary.

Original languageEnglish
Pages (from-to)923-928
Number of pages6
JournalMicroelectronic Engineering
Volume88
Issue number6
DOIs
Publication statusPublished - 2011 Jun 1

Fingerprint

Nanoimprint lithography
anatase
Titanium dioxide
lithography
Annealing
annealing
Nanostructures
shrinkage
Refractive index
Electrooptical devices
refractivity
mirrors
filters
Quantum confinement
protective coatings
Crystal defects
Photochemical reactions
packing density
Optical band gaps
Protective coatings

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

Cite this

Park, Hyeong Ho ; Zhang, Xin ; Lee, Soon Won ; Jeong, Dong Joo ; Lee, Sang Moo ; Kim, Ki Don ; Choi, Dae Geun ; Choi, Jun Hyuk ; Lee, Jihye ; Lee, Eung Sug ; Kang, Ho Kwan ; Park, Hyung-Ho ; Hill, Ross H. ; Jeong, Jun Ho. / Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography. In: Microelectronic Engineering. 2011 ; Vol. 88, No. 6. pp. 923-928.
@article{aa72d8dea5a24eee8f47f61ed97d24f7,
title = "Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography",
abstract = "A direct ultraviolet (UV)-assisted nanoimprinting procedure using photosensitive titanium di-n-butoxide bis(2-ethylhexanoate) is employed in this study for the nanopatterning of anatase titanium dioxide (TiO2) structure. Upon annealing at 400 °C for 1 h, the lateral shrinkage and thickness shrinkage of the TiO2 nanostructure were 39.6{\%} and 52.5{\%}, respectively, which indicated an anisotropic volume loss. During UV irradiation and annealing treatment, the refractive index of UV-irradiated TiO2 film is gradually increased by improvement in the packing density and crystallinity of the film. According to increasing UV exposure time and annealing temperature, the optical band gap (Eg) of UV-irradiated TiO2 film is red-shifted from 3.73 to 3.33 eV due to the formation of lattice defects, vacancies and voids during the photochemical reaction and due to the effect of quantum confinement during annealing treatment. These results suggest that the refractive index and optical Eg of TiO2 nanostructure could be controlled by tuning the UV exposure time and annealing treatment conditions. Nanopatterns of TiO2 fabricated by direct UV-assisted nanoimprint lithography are potential candidates for use in protective coatings for optical mirrors and filters, high-reflectivity mirrors, broadband interference filters and active electro-optical devices where ordered surface nanostructures could be necessary.",
author = "Park, {Hyeong Ho} and Xin Zhang and Lee, {Soon Won} and Jeong, {Dong Joo} and Lee, {Sang Moo} and Kim, {Ki Don} and Choi, {Dae Geun} and Choi, {Jun Hyuk} and Jihye Lee and Lee, {Eung Sug} and Kang, {Ho Kwan} and Hyung-Ho Park and Hill, {Ross H.} and Jeong, {Jun Ho}",
year = "2011",
month = "6",
day = "1",
doi = "10.1016/j.mee.2010.12.018",
language = "English",
volume = "88",
pages = "923--928",
journal = "Microelectronic Engineering",
issn = "0167-9317",
publisher = "Elsevier",
number = "6",

}

Park, HH, Zhang, X, Lee, SW, Jeong, DJ, Lee, SM, Kim, KD, Choi, DG, Choi, JH, Lee, J, Lee, ES, Kang, HK, Park, H-H, Hill, RH & Jeong, JH 2011, 'Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography', Microelectronic Engineering, vol. 88, no. 6, pp. 923-928. https://doi.org/10.1016/j.mee.2010.12.018

Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography. / Park, Hyeong Ho; Zhang, Xin; Lee, Soon Won; Jeong, Dong Joo; Lee, Sang Moo; Kim, Ki Don; Choi, Dae Geun; Choi, Jun Hyuk; Lee, Jihye; Lee, Eung Sug; Kang, Ho Kwan; Park, Hyung-Ho; Hill, Ross H.; Jeong, Jun Ho.

In: Microelectronic Engineering, Vol. 88, No. 6, 01.06.2011, p. 923-928.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography

AU - Park, Hyeong Ho

AU - Zhang, Xin

AU - Lee, Soon Won

AU - Jeong, Dong Joo

AU - Lee, Sang Moo

AU - Kim, Ki Don

AU - Choi, Dae Geun

AU - Choi, Jun Hyuk

AU - Lee, Jihye

AU - Lee, Eung Sug

AU - Kang, Ho Kwan

AU - Park, Hyung-Ho

AU - Hill, Ross H.

AU - Jeong, Jun Ho

PY - 2011/6/1

Y1 - 2011/6/1

N2 - A direct ultraviolet (UV)-assisted nanoimprinting procedure using photosensitive titanium di-n-butoxide bis(2-ethylhexanoate) is employed in this study for the nanopatterning of anatase titanium dioxide (TiO2) structure. Upon annealing at 400 °C for 1 h, the lateral shrinkage and thickness shrinkage of the TiO2 nanostructure were 39.6% and 52.5%, respectively, which indicated an anisotropic volume loss. During UV irradiation and annealing treatment, the refractive index of UV-irradiated TiO2 film is gradually increased by improvement in the packing density and crystallinity of the film. According to increasing UV exposure time and annealing temperature, the optical band gap (Eg) of UV-irradiated TiO2 film is red-shifted from 3.73 to 3.33 eV due to the formation of lattice defects, vacancies and voids during the photochemical reaction and due to the effect of quantum confinement during annealing treatment. These results suggest that the refractive index and optical Eg of TiO2 nanostructure could be controlled by tuning the UV exposure time and annealing treatment conditions. Nanopatterns of TiO2 fabricated by direct UV-assisted nanoimprint lithography are potential candidates for use in protective coatings for optical mirrors and filters, high-reflectivity mirrors, broadband interference filters and active electro-optical devices where ordered surface nanostructures could be necessary.

AB - A direct ultraviolet (UV)-assisted nanoimprinting procedure using photosensitive titanium di-n-butoxide bis(2-ethylhexanoate) is employed in this study for the nanopatterning of anatase titanium dioxide (TiO2) structure. Upon annealing at 400 °C for 1 h, the lateral shrinkage and thickness shrinkage of the TiO2 nanostructure were 39.6% and 52.5%, respectively, which indicated an anisotropic volume loss. During UV irradiation and annealing treatment, the refractive index of UV-irradiated TiO2 film is gradually increased by improvement in the packing density and crystallinity of the film. According to increasing UV exposure time and annealing temperature, the optical band gap (Eg) of UV-irradiated TiO2 film is red-shifted from 3.73 to 3.33 eV due to the formation of lattice defects, vacancies and voids during the photochemical reaction and due to the effect of quantum confinement during annealing treatment. These results suggest that the refractive index and optical Eg of TiO2 nanostructure could be controlled by tuning the UV exposure time and annealing treatment conditions. Nanopatterns of TiO2 fabricated by direct UV-assisted nanoimprint lithography are potential candidates for use in protective coatings for optical mirrors and filters, high-reflectivity mirrors, broadband interference filters and active electro-optical devices where ordered surface nanostructures could be necessary.

UR - http://www.scopus.com/inward/record.url?scp=79952440439&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79952440439&partnerID=8YFLogxK

U2 - 10.1016/j.mee.2010.12.018

DO - 10.1016/j.mee.2010.12.018

M3 - Article

AN - SCOPUS:79952440439

VL - 88

SP - 923

EP - 928

JO - Microelectronic Engineering

JF - Microelectronic Engineering

SN - 0167-9317

IS - 6

ER -