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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: 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.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.

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.


XRD patterns of the TiO2films deposited at different temperatures.
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Fig2: XRD patterns of the TiO2films deposited at different temperatures.

Mentions: Figure 2 shows the XRD patterns of the TiO2 films deposited at different growth temperatures from 175°C to 400°C. Initially, the films deposited at temperatures below 175°C are amorphous. With increasing growth temperature from 200°C to 250°C, the films show anatase crystal phase, with the (101) and (200) peaks in the diffraction patterns. The intensity of the anatase (101) peak reaches a maximum at the growth temperature of 250°C and then decreases dramatically to 300°C, with an emergence of a weak (110) peak from rutile TiO2. At growth temperature above 250°C, the growth mode of the films changes to fast CVD mode, the fast deposition rate causes a strong degradation of the crystallinity of the TiO2 film, as shown by the decrease of the diffraction peaks in the XRD patterns at 300°C to 400°C. Despite of this, very weak (101) peak from anatase TiO2 and (110) peak from rutile TiO2 are observed in the XRD patterns, indicating the formation of a small among of rutile TiO2 in the films. As it was reported that rutile TiO2 is the stablest and densest structure of TiO2 with a mass density of 4.25 g/cm3, while the anatase TiO2 is a metastable and less dense structure, with a smaller density of 3.894 g/cm3 [43]. The increasing tendency of the refractive index from 2.07 to 2.97 in Figure 1, which can be interpreted by the structure change in the films with increasing the growth temperature, is probably due to the film densification with the change from amorphous to anatase as well as the formation of rutile phase [44].Figure 2


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)

XRD patterns of the TiO2films deposited at different temperatures.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: XRD patterns of the TiO2films deposited at different temperatures.
Mentions: Figure 2 shows the XRD patterns of the TiO2 films deposited at different growth temperatures from 175°C to 400°C. Initially, the films deposited at temperatures below 175°C are amorphous. With increasing growth temperature from 200°C to 250°C, the films show anatase crystal phase, with the (101) and (200) peaks in the diffraction patterns. The intensity of the anatase (101) peak reaches a maximum at the growth temperature of 250°C and then decreases dramatically to 300°C, with an emergence of a weak (110) peak from rutile TiO2. At growth temperature above 250°C, the growth mode of the films changes to fast CVD mode, the fast deposition rate causes a strong degradation of the crystallinity of the TiO2 film, as shown by the decrease of the diffraction peaks in the XRD patterns at 300°C to 400°C. Despite of this, very weak (101) peak from anatase TiO2 and (110) peak from rutile TiO2 are observed in the XRD patterns, indicating the formation of a small among of rutile TiO2 in the films. As it was reported that rutile TiO2 is the stablest and densest structure of TiO2 with a mass density of 4.25 g/cm3, while the anatase TiO2 is a metastable and less dense structure, with a smaller density of 3.894 g/cm3 [43]. The increasing tendency of the refractive index from 2.07 to 2.97 in Figure 1, which can be interpreted by the structure change in the films with increasing the growth temperature, is probably due to the film densification with the change from amorphous to anatase as well as the formation of rutile phase [44].Figure 2

Bottom Line: 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.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.

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.