Titanium-doped Indium Oxide Films Research Articles

Effects of H2 plasma treatment on the electrical properties of titanium-doped indium oxide films prepared by polymer-assisted deposition

The effects of hydrogen (H2) plasma on the optical and electrical properties of titanium-doped InO (TIO) grown on glass substrates using polymer-assisted deposition are reported. Samples were exposed to H2 plasma formed by inductively coupled plasma (ICP). After plasma treatment at a power of 100 W, the sheet resistance of the TIO films decreased from 11 000 to 285 Ω/sq. Additionally, the Hall mobility and sheet carrier concentration of the films increased as the ICP source power was increased to 100 W, without affecting the optical transmittance of the films, due to the removal of the polymer residues and the formation of oxygen vacancies.

Structural and Electrical Properties of Titanium-Doped Indium Oxide Films Deposited by RF Sputtering

Titanium-doped indium oxide (ITiO) is a high-quality transparent conducting oxide commonly used as the contact for photovoltaic. The transparent conductive titanium-doped indium oxide (ITiO) films were deposited on Corning glass substrates by RF magnetron sputtering method. The effects of RF sputtering power and Ar gas pressure on the structural and electrical properties of the films were investigated experimentally, using a 2.5 wt% TiO2 -doped In2O3 target. The deposition rate was in the range of around 20 to 60nm/min under the experimental conditions of the gas pressure and the RF Magnetron sputtering power. In this case, the lowest resistivity of 1.2×10-4-cm and the average optical transmittance of 75% were obtained for the ITiO film, prepared at RF power of 300W and Ar gas pressure of 15 mTorr. This resistivity of 1.2×10-4-cm is low enough as a transparent conducting layer in various electro-optical devices and it is comparable with that of ITO or ZnO:Al conducting layer.

Preparation of Titanium-doped Indium Oxide Films by Ultrasonic Spray Pyrolysis Method

Titanium-doped indium oxide (ITiO) films were deposited on soda-lime glass by ultrasonic spray pyrolysis. The optimum conditions of deposition parameters, such as dopant concentration for lowest resistivity were investigated. Phase formation and microstructure of the films were examined by XRD and SEM. AFM was used to obtain the surface topology of the prepared films. The optical transmission and resistivity of films were determined by UV-Vis-NIR spectrophotometer and Van der Pauw method respectively. The resistivity of films depended on the titanium content. The feasibility study of using the ITiO as one of the TCO for solar cell was discussed.

Changes in the structural and electrical properties of vacuum post-annealed tungsten- and titanium-doped indium oxide films deposited by radio frequency magnetron sputtering

Tungsten- and titanium-doped indium oxide (IWO and ITiO) films were deposited at room temperature by radio frequency (RF) magnetron sputtering, and vacuum post-annealing was used to improve the electron mobility. With increasing deposition power, the as deposited films showed an increasingly crystalline nature. Compared with ITiO films, IWO films showed crystallinity at lower RF power. IWO films are partially crystallized at 10 W deposition power and become nearly fully crystalline at 20 W. ITiO films are fully crystalline only at 75 W. For this reason, film thickness has a greater impact on the electrical properties of IWO films than ITiO films. Vacuum post-annealing is more effective in improving electron mobility for amorphous than for (partially) crystalline IWO and ITiO films. Changes in the electrical properties of ITiO films can be better controlled as a function of annealing temperature than those of IWO films. Finally, post annealed 308 nm-thick IWO and 325 nm-thick ITiO films have approximately 80% transmittance in visible and near infrared wavelengths (up to 1100 nm), while their sheet resistances decrease to 9.3 and 10 Ω/□, and their electron mobilities are 51 cm 2V − 1 s − 1 and 50 cm 2V − 1 s − 1 , respectively, making them suitable for use as Transparent Conductive Oxide layers of low bandgap solar cells.

Electrical properties of vacuum-annealed titanium-doped indium oxide films

Titanium-doped indium oxide (ITiO) films were deposited on Corning glass 2000 substrates at room temperature by radio frequency magnetron sputtering followed by vacuum post-annealing. With increasing deposition power, the as-deposited films showed an increasingly crystalline nature. As-deposited amorphous ITiO films obtained at 20 W began to crystallize at the annealing temperature of 155 °C. Although there was no significant change in the crystalline structure of the films, electron mobility improved gradually with further increase in the annealing temperature. After post-annealing at 580 °C, the highest electron mobility of 50 cm 2 V −1 s −1 was obtained. Compared with the amorphous ITiO films, the ITiO films with a certain degree of crystallinity obtained at high deposition power were less affected by the vacuum annealing. Their electron mobility also improved due to post-annealing, but the increase was insignificant. After post-annealing, the optical transmission of the 325 nm-thick ITiO films showed approximately 80% at wavelengths ranging from 530 to 1100 nm, while the sheet resistance decreased to 10 Ω/sq. This makes them suitable for use as transparent conductive oxide layers of low bandgap solar cells.

Fabrication of Titanium-Doped Indium Oxide Films for Dye-Sensitized Solar Cell Application Using Reactive RF Magnetron Sputter Method

To develop high-efficiency transparent conductive oxide glass in a longer wavelength zone for dye-sensitized solar cell (DSC) application, we fabricate titanium-doped indium oxide (ITiO) films on a soda-lime glass substrate by an RF magnetron sputtering. The ITiO films showed a minimum resistivity of 1.25 times 10-3 Omega ldr cm. The transmittance increases from 80% at 450 nm to 90% at 700 nm in the visible spectrum. From the atomic force microscopy result, the surface roughness of the sample showed a change from 10 to 50 nm with annealing temperature. From the XPS result, the concentration ratio (%) for In, Ti, and O was 27 : 2 : 42. The annealing treatment on the ITiO films improves the photovoltaic characteristics of the ITiO-based DSCs, and energy conversion efficiency (eta) is 5.79% (FF: 0.62, Voc: 0.71 V, Jsc: 13.23 mA/cm2) at 100-mW/cm2 light intensity.

Influence of O2/Ar Ratio on the Properties of Transparent Conductive Titanium-Doped Indium Oxide Films by DC Radio-Frequency Sputtering

AbstractTitanium doped indium oxide (TIO) thin films were deposited on glass substrate by DC sputtering with different O2/Ar gas ratios at 330 °C. The effects of sputtering on the structural, morphologic, optical and electrical characteristics of TIO thin films were investigated by XRD, Hall measurement and optical transmission spectroscopy. The deposited films exhibited polycrystalline in the preferred (222) orientation, with higher mean grain size and lower resistivity 3.37 ×10-4Ω·cm at O2/Ar ratio of 1/10. The average optical transmittance of the films is over 90%, and the transmittance has no evident change with changing O2/Ar ratio.

Transparent conductive titanium-doped indium oxide films prepared by a magnetic null discharge sputter source

Titanium-doped indium oxide (ITiO) films were prepared on soda-lime glass substrate using a magnetic null discharge (MND) sputter source. The ITiO thin films containing 10 wt.% Ti showed the minimum resistivity of ρ = 5.5 × 10 −3 Ω cm. The optical transmittance increases from 70% at 450 nm to 80% at 700 nm in visible spectrum. Photoelectron peaks for In 3d, Ti 2p, O 1s and C 1s were detected for the ITiO film in the binding energy range of 0–1100 eV. The surface roughness of the sample showed a change from 10 nm to 50 nm. The ITiO film used for TCO layer of DSCs exhibited an energy conversion efficiency of about 3.8% at light intensity of 100 mW/cm 2.

Opto-electrical properties of Ti-doped In 2O 3 thin films grown by pulsed laser deposition

By ablating titanium containing In 2O 3 target with a KrF excimer laser, highly conducting and transparent films on quartz were obtained to investigate the effects of growth temperature and oxygen pressure on the structural, optical and electrical properties of these films. We find that the transparency of the films depends more on the growth temperature and less on the oxygen pressure. Electrical properties, however, are found to be sensitive to both the growth temperature and oxygen pressure. We report in this paper that a growth temperature of 500 °C and an oxygen pressure of 7.5 × 10 −7 bar lead to titanium-doped indium oxide films which have high mobility (up to 199 cm 2 V −1 s −1), low resistivity (9.8 × 10 −5 Ω cm), and relatively high transmittance (∼88%).

Titanium-doped indium oxide films prepared by d.c. magnetron sputtering using ceramic target

Polycrystalline thin films of Ti-doped indium oxide (indium–titanium-oxide, ITiO) were prepared by d.c. magnetron sputtering and their electrical and optical properties were investigated. Doping of Ti was effective in improvement of the electroconductivity of the indium oxide: the electrical resistivity of 1.7 × 10−3 Ω cm of non-doping decreased to minimum value of 1.8 × 10−4 Ω cm at 2.4 at.% Ti-doping when the films were deposited at 300 °C. The polycrystalline ITiO films of 0.8–1.6 at. % Ti-doping showed the high Hall mobilitiy (82–90 cm2 V−1 s−1) and the relatively low carrier density (2.4–3.5 × 1020 cm−3) resulting in characteristics of both low resistivity (2.1–3.0 × 10−4 Ω cm) and high transmittance in the near-infrared region (over 80% at 1550 nm), which cannot be shown in the conventional Sn-doped indium oxide (ITO) films.