Characteristics Of Indium Tin Oxide Research Articles

Ion behavior impact on ITO thin film fabrication via DC magnetron sputtering with external anode

“Sputtering damage” arising from high-energy negative ions plays a pivotal role in shaping the characteristics of indium tin oxide (ITO) thin films deposited through direct-current magnetron sputtering (DCMS). To mitigate this issue, we employ DCMS with an external anode. The increment in anode bias VA from 0 to +60V effectively diminishes the average kinetic energy of negative ions such as O−, O2− and InO− by reducing the cathode voltage. Additionally, the flux of positive ions (e.g., Ar+, In+, Sn+, O+) increases and their ion energy distribution functions (IEDFs) exhibit supplementary peaks at plasma potentials. Both facilitate film crystallization, as evidenced by the structural transition from subgrain to grain formations. Heightened surface roughness markedly enhances optical transmittance. Due to a reduced oxygen sticking coefficient, films grown with higher VA values exhibit increased oxygen vacancies, which serve as the primary charge carriers for ITO films. Consequently, ITO films attain their lowest resistivity (7.81×10−4Ωcm) and highest optical transmittance (78.71 %) at VA = +60V. This investigation underscores the significant influence of the external anode bias on both ion behavior and film growth, providing a viable approach to enhance the electrical and optical properties of ITO films.

Radiation-Induced Surface Wettability Enhancement of an Indium Tin Oxide and Titanium Oxide Film-Coated Sapphire

Abstract Surface wettability is an important parameter that affects nucleate boiling. Irradiation can alter the surface wettability on metal surfaces without altering the surface macrostructure. The wettability characteristics of indium tin oxide and TiO2 film-coated sapphire substrates following gamma-ray and electron beam irradiation were experimentally investigated. A sapphire plate was exposed to gamma rays and electron beams. Within the irradiation dose, no evident change in the sapphire surface color was found. The surface contact angle decreased after irradiation, and surface wettability was enhanced with more irradiation. After irradiation, the contact angle recovered with time. The related mechanism is possible due to the absorption/desorption of hydroxyl groups. Our results indicate that the irradiation method can be used in indium tin oxide film-coated sapphire experiments to study nucleate boiling.

One-Step Etching Characteristics of ITO/Ag/ITO Multilayered Electrode in High-Density and High-Electron-Temperature Plasma.

This paper presents the dry etching characteristics of indium tin oxide (ITO)/Ag/ITO multilayered thin film, used as a pixel electrode in a high-resolution active-matrix organic light-emitting diode (AMOLED) device. Dry etching was performed using a combination of H2 and HCl gases in a reactive ion etching system with a remote electron cyclotron resonance (ECR) plasma source, in order to achieve high electron temperature. The effect of the gas ratio (H2/HCl) was closely observed, in order to achieve an optimal etch profile and an effective etch process, while other parameters—such as the radio frequency (RF) power, ECR power, chamber pressure, and temperature—were fixed. The optimized process, with an appropriate gas ratio, constitutes a one-step serial dry etch solution for ITO and Ag multilayered thin films.

Effect of post-annealing in oxygen environment on ITO thin films deposited using RF magnetron sputtering

This work demonstrated the effect of post-annealing on electrical and optical characteristics of indium tin oxide (ITO) thin films. ITO with 100 nm thickness was successfully deposited using radio frequency (RF) magnetron sputtering in oxygen-free environment on sodalime glass substrate without substrate heating. Post-annealing treatment was carried out on ITO thin films in oxygen environment. Different annealing temperatures were studied on the films from 300°C up to 600 °C. The annealing time and oxygen flow rate were kept constant. As the annealing temperature increase, the structure of the thin film’s changes from amorphous to polycrystalline which lead to the effect of enhanced hall mobility. Annealing temperature strongly influence the optical transmission in visible region. It leads to higher transmittance of ITO thin films and is suitable for a blue light emitting diode (LED) application. In addition, higher annealing temperature also enhances film electrical performance. Further characterization of the deposited films was done using hall measurement, UV-Vis spectrophotometer and atomic force microscopic (AFM) to show the improvement on their electrical and optical characteristic. The optical and electrical characteristics of the films have been compared with each other.

Silicon ring resonator electro-optical modulator utilizing epsilon-near-zero characteristics of indium tin oxide

One crucial component in optical communication systems is the optical modulator. It links between the electric and optical domains as it transforms the electric signal into an optical stream. Electro-optical modulation is a very popular scheme. Recently, indium tin oxide (ITO) has been intensively used in optical modulators due to its epsilon-near-zero characteristics. A silicon electro-optic ring resonator modulator is proposed in terms of the outspread application of ITO. An extinction ratio of about 14 dB as well as an insertion loss of 0.075 dB are achieved at a standard telecommunication wavelength of 1.55 microns. The design has low losses, high efficiency, and compact size.

A highly conductive and flexible metal mesh/ultrathin ITO hybrid transparent electrode fabricated using low-temperature crystallization

The low-temperature processing of transparent electrodes on polymer substrates is an increasingly important issue in lightweight and flexible optoelectronic devices and low-temperature processing is essential since most polymer substrates cannot withstand high temperatures. We analyzed the electrical and optical characteristics of indium tin oxide (ITO) films according to the various crystallization conditions and confirmed that the low-temperature crystallized ITO has a rhombohedral structure. The ultrathin ITO films were crystallized at a temperature of 250 °C, which is lower than the glass transition temperature of polyimide substrates, and a hybrid transparent electrode with a metal mesh was formed. Our hybrid transparent electrode had a high transmittance of 77.4% and a low sheet resistance of 6.3 Ω/sq. After 1000 bending cycles at a bending radius of 6 mm, the hybrid transparent electrode maintained a sheet resistance of 6.5 Ω/sq. We applied rhombohedral ITO to the device rather than the commonly used cubic ITO, and as a result, it showed excellent electrical properties and better bending-stress stability.

Conductive Characteristics of Indium Tin Oxide Thin Film on Polymeric Substrate under Long-Term Static Deformation

The objective of this study is to investigate the effect of long-term static bending on the conductive characteristics of indium tin oxide (ITO) thin film in flexible optoelectronics. Two types of substrate are considered, namely ITO on polyethylene naphthalate (ITO/PEN) and ITO on polyethylene terephthalate (ITO/PET). Electrical properties of the ITO/PEN and ITO/PET sheets are measured in situ under static bending at various radii of curvature. Experimental results indicate that no significant change in electrical resistance of the ITO/PEN and ITO/PET sheets is found for compressive bending after 1000 h at a curvature radius of 10 mm or larger. However, the ITO/PEN and ITO/PET sheets are seriously damaged under a tensile bending of 10 mm radius and 5 mm radius, respectively. The given ITO/PET sheet exhibits a greater resistance to long-term mechanical bending than the ITO/PEN one, which is attributed to the effect of stiffness and thickness of substrate. As the given PET substrate has a lower stiffness and thickness than the PEN one, ITO thin film in the ITO/PET sheet has a smaller stress given a bending radius. Consequently, a smaller extent of change in the electrical conductance of ITO thin film is found in the ITO/PET sheet.

Effects of plasma treatment time on surface characteristics of indium-tin-oxide film for resistive switching storage applications

In this paper, we implement a post-oxidation method to modify surface characteristics of indium tin oxide (ITO) films by using an O2 inductively coupled plasma (ICP) treatment. Based on field emission-scanning electron microscope (FE-SEM) and atomic force microscope (AFM) analysis, we found that the surface morphologies of the ITO films become slightly flatter after the O2 plasma treatment. The optical characteristics and X-ray diffraction (XRD) experiments of either pure ITO or O2 plasma treated ITO films were also verified. Even though the XRD results showed no difference from bulk crystallizations, the oxygen concentrations increased at the film surface after O2 plasma treatment, according to the XPS inspection results. Moreover, this study investigated the effects of two different plasma treatment times on oxygen concentration in the ITO films. The surface sheet resistance of the plasma treated ITO films became nearly non-conductive when measured with a 4-point probe. Finally, we applied the O2 plasma treated ITO films as the insulator in resistive random access memory (RRAM) to examine their potential for use in resistive switching storage applications. Stable resistance switching characteristics were obtained by applying the O2 plasma treatment to the ITO-based RRAM. We also confirmed the relationship between plasma treatment time and RRAM performance. These material analyses and electrical measurements suggest possible advantages in using this plasma treatment technique in device fabrication processes for RRAM applications.

Resistance Switching Characteristics Induced by O2 Plasma Treatment of an Indium Tin Oxide Film for Use as an Insulator in Resistive Random Access Memory.

In this study, an O2 inductively coupled plasma (ICP) treatment was developed in order to modify the characteristics of indium tin oxide (ITO) film for use as an insulator in resistive random access memory (RRAM). After the O2 plasma treatment, the previously conductive ITO film is oxidized and becomes less conductive. In addition, after capping the same ITO material for use as a top electrode, we found that the ITO/ITO(O2 plasma)/TiN device exhibits very stable and robust resistive switching characteristics. On the contrary, the nontreated ITO film for use as an insulator in the ITO/ITO/TiN device cannot perform resistance switching behaviors. The material analysis initially investigated the ITO film characteristics with and without O2 plasma treatment. The surface was less rough after O2 plasma treatment. However, the molar concentration of each element and measured sheet resistance results for the O2-plasma-treated ITO film were dramatically modified. Next, electrical measurements were carried out to examine the resistance switching stability under continuous DC and AC operation in this ITO/ITO(O2 plasma)/TiN device. Reliability tests, including endurance and retention, also proved its capability for use in data storage applications. In addition to these electrical measurements, current fitting method experiments at different temperatures were performed to examine and confirm the resistance switching mechanisms. This easily fabricated device, using a simple material combination, achieves excellent performance by using ITO with an O2 plasma treatment and can further the abilities of RRAM for use in remarkable potential applications.

Impacts of Co doping on ZnO transparent switching memory device characteristics

The resistive switching characteristics of indium tin oxide (ITO)/Zn1−xCoxO/ITO transparent resistive memory devices were investigated. An appropriate amount of cobalt dopant in ZnO resistive layer demonstrated sufficient memory window and switching stability. In contrast, pure ZnO devices demonstrated a poor memory window, and using an excessive dopant concentration led to switching instability. To achieve suitable memory performance, relying only on controlling defect concentrations is insufficient; the grain growth orientation of the resistive layer must also be considered. Stable endurance with an ON/OFF ratio of more than one order of magnitude during 5000 cycles confirmed that the Co-doped ZnO device is a suitable candidate for resistive random access memory application. Additionally, fully transparent devices with a high transmittance of up to 90% at wavelength of 550 nm have been fabricated.

Resistive Switching Mechanism of Oxygen-Rich Indium Tin Oxide Resistance Random Access Memory

This letter investigates the double-ended resistive switching characteristics of indium tin oxide (ITO) resistance random access memory (RRAM). Resistive switching can be achieved around both the active TiN electrode and the inert Pt electrode. In addition, complementary resistance switching (CRS) characteristics can be observed without current compliance during dc voltage sweep operations. Electrical measurement data fitting results indicate that the oxygen-rich ITO near top and bottom electrodes works as a double-ended resistive switching layer. Based on the analysis of the current conduction mechanism, we propose a physical model to interpret the CRS behaviors in ITO RRAM devices.

A study of the characteristics of indium tin oxide after chlorine electro-chemical treatment

In this work, we investigate the influence of a chlorine-based electro-chemical surface treatment on the characteristics of indium tin oxide (ITO) including the work function, chemical composition, and phase transition. The treated ITOs were characterized using X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS), 4-point probe measurements, and grazing incidence X-ray diffraction (GI-XRD).We confirmed a change of the chemical composition in the near-surface region of the ITO and the formation of indium-chlorine (In-Cl) bonds and surface dipoles (via XPS). In particular, the change of the electro-static potential in the outer surface was caused by chlorination.Due to the vacuum-level shift after the electro-chemical treatment in a dilute hydrochloric acid, the ITO work function was increased by ∼0.43eV (via UPS); furthermore, the electro-negativity of the chlorine anions attracted electrons to emit them from the hole transport layer (HTL) to the ITO anodes, resulting in an increase of the hole-injection efficiency.

Computational modeling of optical properties in aluminum nanolayers inserted in ZnO for solar cell electrodes.

Numerical simulations were used to study the transmittances (Ts) of ZnO/Al/ZnO (ZAZ) films with Al thicknesses between ∼1 and 40nm. The simulations are validated using previously reported experimental results. Multilayers with Al thicknesses between ∼1 and 10nm are shown to have average Ts between ∼75% and 90%, which decreased farther to ∼63 and 41% for the Al layer thicknesses of 20 and 40nm, respectively. Variations in the ZnO thickness between ∼10 and 100nm are shown to have little effect on the optical properties of the model multilayers for a given Al thickness. The reliability of the numerical simulations is tested by comparing them with experimental measurements on films produced using similar interlayer thicknesses. These are also shown to be comparable to the performance characteristics of indium tin oxide (ITO) anodes that are used currently in organic solar cells (OSCs) and organic light emitting diodes (OLEDs).

Characteristics of Indium Tin Oxide (ITO) Nanoparticles Recovered by Lift-off Method from TFT-LCD Panel Scraps.

In this study, indium-tin-oxide (ITO) nanoparticles were simply recovered from the thin film transistor-liquid crystal display (TFT-LCD) panel scraps by means of lift-off method. This can be done by dissolving color filter (CF) layer which is located between ITO layer and glass substrate. In this way the ITO layer was easily lifted off the glass substrate of the panel scrap without panel crushing. Over 90% of the ITO on the TFT-LCD panel was recovered by using this method. After separating, the ITO was obtained as particle form and their characteristics were investigated. The recovered product appeared as aggregates of particles less than 100 nm in size. The weight ratio of In/Sn is very close to 91/9. XRD analysis showed that the ITO nanoparticles have well crystallized structures with (222) preferred orientation even after recovery. The method described in this paper could be applied to the industrial recovery business for large size LCD scraps from TV easily without crushing the glass substrate.

Post-Annealing Effects on ITO Thin Films RF Sputtered at Different Thicknesses on Si and Glass

We report on electrical, optical and surface morphological characteristics of indium tin oxide (ITO) thin films. The ITO was deposited by radio frequency (RF) magnetron sputtering on Si and glass substrates at different thicknesses of 125 nm and 239 nm. Post-annealing treatment was conducted on the samples at temperature of 500°C and 600°C. From Hall Effect measurement, the lowest resistivity was measured as 4.4 × 10-4 Ωcm and 4.5 × 10-4 Ωcm corresponding to the 239 nm and 125 nm ITO sample, respectively, after post-annealed at 600°C. Using UV-Vis spectrophotometer, the highest transmittance of ~84% at 470 nm was observed with respect to the 125 nm ITO thin films after post-annealed at 500°C. Furthermore, the 500°C post-annealed 125 nm thin film shows highest carrier concentrations of more than 1021 cm-3 and smoothest surface morphology of 0.5 nm root-mean-square, RMS. It is clearly shown that post-annealing treatment on ITO thin films is able to enhance the electrical and optical transmittance properties as compared to the as deposited films.

Effects of flow rate of oxygen and hydrogen gases on characteristics of ITO thin films for OLEDs

We have investigated the effect of ambient gases on the structural, electrical and optical characteristics of indium tin oxide (ITO) thin films intended for use as anode contacts in organic light emitting diode (OLED) devices. These ITO thin films are deposited by radio frequency magnetron sputtering under different ambient gases (Ar, Ar+O2 and Ar+H2) at 300°C. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0·5 to 5 sccm and from 0·1 to 1 sccm, respectively. The intensity of the (400) peak in the ITO thin films increases with increasing H2 flow rate, while the (400) peak was nearly invisible in an atmosphere of Ar+O2. The electrical resistivity of the ITO thin films increases with increasing O2 flow rate, whereas the electrical resistivity decreases sharply under an Ar+H2 atmosphere and is nearly similar regardless of the H2 flow rate. The change of electrical resistivity with changes in the ambient gas composition is mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. All the films show an average transmittance of >80% in the visible range. The optical band gap of the ITO films increases with increasing H2 flow rates, whereas the optical band gap of the ITO films deposited in an O2 atmosphere decreases with increasing O2 flow rates. The current density and the luminance of the OLED devices with ITO thin films deposited in 1 sccm of H2 ambient gas are the highest among all the films. The optical band gap energy of ITO thin films plays a major role in OLED device performance, especially the current density and luminance.

A study of the surface reaction on the etched ITO thin films by using inductively coupled plasma

In this study, we investigated the etching characteristics of indium tin oxide (ITO) thin films at CF4/Ar plasma. The maximum etch rate of 29.8 nm/min for the ITO thin films was obtained at CF4/Ar (=80/20) gas mixing ratio. The standard conditions were the RF power of 800 W, the DC-bias voltage of −150 V, the process pressure of 2 Pa, and the substrate temperature of 40 °C. Corresponding to these etching conditions, chemical reaction of the etched ITO surface has been studied by X-ray photoelectron spectroscopy measurement to investigate the chemical reactions between the surfaces of ITO thin film and etch species. The preferential losses on the etched surfaces were investigated using atomic force microscopy.

저온 E Beam 증착 공정으로 제조된 폴리에테르설폰 유연기판용 ITO 필름 특성 연구

The characteristics of indium tin oxide (ITO) thin film deposited on polyethersulfone (PES) film by low temperature E beam has been studied for the flexible photovoltaic devices. It was found that the substrate temperature in the deposition process affected the crystallization behavior of ITO during the post low temperature annealing process. Higher substrate temperature resulted in the increase of crystallinity of annealed ITO. Consequently, the lowering of sheet resistivity and better transmittance were obtained. Crystallization of ITO during the annealing process was facilitated by using oxygen gas in the deposition process and resulted in the enhancement on sheet resistivity and transmittance of ITO. The surface roughness of PES film prohibited the crystallization of ITO during the annealing process and it caused the increase of sheet resistivity and the decrease of transmittance of ITO.

Current-Voltage Characteristics of ITO/p-Si and ITO/n-Si Contact Interfaces

We investigated the electrical contact characteristics of indium tin oxide (ITO)/doped hydrogenated amorphous silicon (a-Si:H) junctions. For efficient collection of photo-generated carriers, photovoltaic and photodetector devices require good ohmic contacts with transparent electrodes. The amorphous-Si thin films were sputter deposited on ITO coated glass substrates. As-deposited p-type a-Si:H on ITO formed nearly ohmic type contacts and further annealing did not improve the contact characteristics. On the other hand, as-deposited n-type a-Si:H on ITO formed an ohmic contact, while further annealing resulted in a Schottky type contact. The ITO contact with p-type silicon semiconductor is a robust ohmic contact for Si based optoelectronic devices.

The effect of ITO annealing on electrical characteristic of GaN based LED

In the recent years，more and more light-emitting diodes use indium tin oxide (ITO) as the current spreading layer. But if there is not any treatment, the electrical properties of light emitting diode are very poor. So to get excellent electrical properties of light emitting diode, annealing is an effective method to improve the electrical properties of light emitting diode using indium tin oxide as the current spreading layer. However, the annealing time and temperature can affect the electrical property of light emitting diode individually. In order to investigate this problem，we measured the series resistance and ideality factor of the light emitting diode got under different annealing time and annealing temperature. According to the model proposed by Jay M. Shah，we can inferred the characteristics of indium tin oxide and P-type GaN contact. The results showed that: the electrical properties of the light-emitting diode can reach an excellent value with increasing annealing temperature and time, and if continuing to increase in temperature or time, it can lead to a decline in light-emitting diode electrical properties. It is very helpful to optimize the annealing temperature and time and manufacture excellent electrical properties of devices.