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Structure and photoluminescence of the TiO2 films grown by atomic layer deposition using tetrakis-dimethylamino titanium and ozone.

Jin C, Liu B, Lei Z, Sun J - Nanoscale Res Lett (2015)

Bottom Line: Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C.The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C.Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Weijin Road 94, Tianjin, 300071 China.

ABSTRACT
TiO2 films were grown on silicon substrates by atomic layer deposition (ALD) using tetrakis-dimethylamino titanium and ozone. Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C. The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C. Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm. The red band exhibits a strong correlation with defects of the under-coordinated Ti(3+) ions, and the green band shows a close relationship with the oxygen vacancies on (101) oriented anatase crystal surface. A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti(3+) ions transform to surface oxygen vacancies in the anatase TiO2 film annealing at temperature from 800°C to 900°C in N2 atmosphere.

No MeSH data available.


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Models for photoluminescence from the electronic transitions of trap states in anatase and rutile TiO2.
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Fig11: Models for photoluminescence from the electronic transitions of trap states in anatase and rutile TiO2.

Mentions: From the results of this study and the comprehensive study of the luminescent defects in TiO2 nanocrystals in ref. [48-51], the proposed model for PL in the ALD TiO2 films is illustrated in Figure 11. After electrons are excited from the valence band to the conduction band of TiO2, some electrons are captured by the electron traps associated with under-coordinated Ti atoms, which located at 0.7 to 1.6 eV below the conduction band edge. Radiative recombination of the electrons trapped around under-coordinated Ti atoms with the holes in the valence band contributes to the red band at around 600 to 620 nm. In addition, the green band at around 500 to 520 nm may be from the radiative recombination of free electrons with holes trapped around surface oxygen vacancies, which were located at 0.7 to 1.4 eV above the valence band edge. In addition, the near-infrared emission band at around 820 nm is from the defects in rutile TiO2, which are related to the radiative recombination of electrons in conduction band with hole traps on the (110) and (110) facets of oxygen vacancies [49].Figure 11


Structure and photoluminescence of the TiO2 films grown by atomic layer deposition using tetrakis-dimethylamino titanium and ozone.

Jin C, Liu B, Lei Z, Sun J - Nanoscale Res Lett (2015)

Models for photoluminescence from the electronic transitions of trap states in anatase and rutile TiO2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385123&req=5

Fig11: Models for photoluminescence from the electronic transitions of trap states in anatase and rutile TiO2.
Mentions: From the results of this study and the comprehensive study of the luminescent defects in TiO2 nanocrystals in ref. [48-51], the proposed model for PL in the ALD TiO2 films is illustrated in Figure 11. After electrons are excited from the valence band to the conduction band of TiO2, some electrons are captured by the electron traps associated with under-coordinated Ti atoms, which located at 0.7 to 1.6 eV below the conduction band edge. Radiative recombination of the electrons trapped around under-coordinated Ti atoms with the holes in the valence band contributes to the red band at around 600 to 620 nm. In addition, the green band at around 500 to 520 nm may be from the radiative recombination of free electrons with holes trapped around surface oxygen vacancies, which were located at 0.7 to 1.4 eV above the valence band edge. In addition, the near-infrared emission band at around 820 nm is from the defects in rutile TiO2, which are related to the radiative recombination of electrons in conduction band with hole traps on the (110) and (110) facets of oxygen vacancies [49].Figure 11

Bottom Line: Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C.The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C.Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Weijin Road 94, Tianjin, 300071 China.

ABSTRACT
TiO2 films were grown on silicon substrates by atomic layer deposition (ALD) using tetrakis-dimethylamino titanium and ozone. Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C. The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C. Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm. The red band exhibits a strong correlation with defects of the under-coordinated Ti(3+) ions, and the green band shows a close relationship with the oxygen vacancies on (101) oriented anatase crystal surface. A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti(3+) ions transform to surface oxygen vacancies in the anatase TiO2 film annealing at temperature from 800°C to 900°C in N2 atmosphere.

No MeSH data available.


Related in: MedlinePlus