Electrical Properties Of Indium Tin Oxide Films Research Articles

INVESTIGATION OF STRUCTURAL, OPTICAL, AND ELECTRICAL PROPERTIES OF ITO FILMS DEPOSITED AT DIFFERENT PLASMA POWERS: ENHANCED PERFORMANCE AND EFFICIENCY IN SHJ SOLAR CELLS

This article presents an investigation into the structural, optical, and electrical properties of Indium Tin Oxide (ITO) films that were deposited utilizing various plasma powers. The transmittance values in the visible region were measured, revealing that the ITO film deposited at 2050 W exhibited the highest transmittance (81%). Additionally, the sheet resistance values of all films were analyzed, indicating that the ITO film deposited at 2050 W had the lowest sheet resistance (64.9 Ω/sq). By means of XRD analysis, the structural properties of the films were meticulously scrutinized, and the distinctive diffraction peaks associated with the ITO films were successfully identified. Notably, the ITO film deposited at 2050 W demonstrated superior performance compared to the other films deposited using various plasma powers. Finally, we report a noteworthy efficiency of 17.03% achieved in the SHJ solar cell fabricated with the ITO film deposited at 2050 W on a 5x5 cm2 n-type Si substrate.

Tuning the optical and electrical properties of HiPIMS-ITO films by variation of annealing temperature

High power impuls magnetron sputtering (HiPIMS) deposits high quality films due to high ionization fraction. In this work, Indium tin oxide (ITO) films are deposited by HiPIMS methord. The effects of annealing temperature under nitrogen environment on the crystal structure, optical properties and electrical properties of ITO films were investigated. The properties of the films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Hall measurement system (Hall), and UV-Vis spectrophotometer. The results showed that the average visible transmittance of the annealed ITO film reached 83.5%. The XRD results show that the ITO film grain size slightly increased after annealing. The mobility increases after annealing. This study proves that HiPIMS deposited ITO thin film is very superior to low temperature processing, and the grown thin film can be used in LEDs and solar cells.

Effects of ambient high-temperature annealing on microstructure, elemental composition, optical and electrical properties of indium tin oxide films

500 nm-thickness indium tin oxide (ITO) films were deposited onto quartz glass substrates and annealed at 700–1000 °C for 1 h. Microstructure, elemental composition, optical and electrical properties of ITO films were systematically studied. It is found that the crystalline is cubic bixbyite, and preferred orientation changes from mainly (222) to (400) with the increasing temperature. Obvious changes are also observed in morphology of ITO films during the ambient high-temperature annealing. ITO film annealed up to 1000 °C is still stable Sn doped In2O3, oxygen defects decreases and adsorbed oxygen increases. The resistivity of ITO films after annealed at 700 and 800 °C firstly increases slightly and then increases sharply, when annealing temperature is increased to 900 and 1000 °C. Average transmittance of these films was 70%–80% and their optical band gap shifts to lower energy with the increase of the annealing temperature.

Effect of Sputtering Power on the Optical and Electrical Properties of ITO Films on a Flexible Fluorphlogopite Substrate

AbstractIn this study, magnetron sputtering is implemented to adjust the sputtering power from 156 to 306 W at room temperature, and thin film samples of indium tin oxide (ITO) on a flexible fluorphlogopite substrate are taken. With the increase in power, the resistivity of the film first decreases and then increases. The resistivity is at least 1.51 × 10–3 Ω cm at 276 W, and the highest resistivity is 2.93 × 10–2 Ω cm at 156 W. The average light transmittance of the film (400–800 nm) decreases with the increase in power within the range of 156–276 W, The highest average transmittance is 92.6% at 156 W. The quality factor of the film first rises and then decreases as the power increases, it is as high as 4.47 × 10–3 Ω–1sq at 276 W. All the AFMs show that the roughness of the sample does not significantly change with power. The SEM picture shows that as the power increases from 156 to 276 W, the grain size increases slightly. All samples are bent 1200 times around a steel cylinder, and the sheet resistance does not change more than 5%.

Effect of sputtering pressure on the optical and electrical properties of ITO film on fluorphlogopite substrate

The van der Waals forces between the layers of fluorphlogopite make it flexible, and its stability under strong acid, strong alkali, and high temperature conditions has potential applications as a new base material for flexible electronics. In this article, using magnetron sputtering technology, the focus is on the influence of the change of sputtering pressure on the photoelectric properties of the prepared ITO thin film. In this study, indium tin oxide (ITO) film samples were prepared on a fluorphlogopite substrate using the magnetron sputtering technique and adjusting the sputtering pressure from 0.6 Pa to 11 Pa at room temperature. The film was characterized using SEM, XRD, four-probe tester, and ultraviolet–visible spectrophotometer to understand its microstructure and photoelectric properties. The number of bending times of the sample's square resistance around the steel cylinder characterized its flexibility. The results showed that the sample crystal grains decreased significantly with the increase in pressure. Further, it can be seen from SEM images that all samples contained extremely uniform particles. The light transmittance and resistivity of the sample synthesized below 3 Pa increased sharply with the increase of sputtering pressure, and the change above 3 Pa tended to be stable. The average transmittance of visible light in the wavelength range of 400–800 nm ​​is higher than 86%, the highest being 92.7%; the sputtering pressure of 0.6 Pa yielded a sample with the lowest resistivity of 1.51 × 10−3 Ωcm. All the samples were bent 1200 times around a steel cylinder with a radius of 3.65 mm, and the change in sheet resistance did not exceed 5%.

Optical and electrical properties of ITO film on flexible fluorphlogopite substrate

Indium Tin Oxide (ITO) films were prepared, at room temperature, on a fluorphlogopite substrate using magnetron sputtering technology. At various temperatures of 500 °C, 600 °C, 700 °C, 800 °C, and 900 °C, the samples were (had) annealed for 2 h (a 2-h duration). The results showed improvement in the crystalline performance of ITO film at selected annealing temperatures, with a significant reduction in resistivity at 800 °C. The lowest resistivity is 4.08 × 10−4 Ω-cm, which is nearly an order of magnitude lower than the unannealed sample. All samples have an average light transmittance above 85% in the visible light range (400–800 nm), and with increasing annealing temperature, the average light transmittance tends to decrease. Besides, at the sensitive wavelength of 550 nm, the light transmittance is as high as 93.74%. The sheet resistance testing of the sample was through the number of bending times, which revealed that with the increase of the number of bending, the sheet resistance increases. However, after 1200 bending times, the change rate of the sheet resistance remains below 5%. Thus, the ITO film prepared on the flexible fluorphlogopite substrate revealed excellent optical and electrical properties, good flexibility, and improved stability after high-temperature annealing, which guarantees successful application in flexible electronic devices.

Role of RF Magnetron Sputtering Power on Optical and Electrical Properties of ITO Films on Soda-Lime Glass Substrates

The optical and electrical properties of indium tin oxide (ITO) thin films grown on soda-lime glass substrates using a radio frequency (RF) magnetron sputtering technique were studied as a function of the sputtering RF power. Fixed 100 nm thickness of ITO films were deposited on the soda-lime glass substrates at 300 °C, using RF powers ranging between 50 to 150 W. The optical and electrical properties of the sputtered ITO films were characterized by Ultraviolet–Visible Spectroscopy (UV-Vis), Hall Effect Measurement and Atomic Force Microscope (AFM). Varying the substrate temperature and RF sputtering power affected surface roughness to decrease from 5.80, 4.59 and 3.46 nm while the resistivity also decreased from 18.73 x 10−4, 6.484 x 10−4 and 2.421 x 10−4 Ω.cm. Deposition of ITO thin films on soda-lime glass substrates by RF magnetron sputtering at 300 °C substrate temperature contributed to 74 to 79 % of optical transmittance in the 450 nm region. Results of this study suggested that a better performance of both optical transparency and electrical conductivity of ITO films can be achieved by operating at high temperature substrate and high level of sputtering power.

Highly Transparent Conducting Indium Tin Oxide Thin Films Prepared by Radio Frequency Magnetron Sputtering and Thermal Annealing.

High-quality ITO (indium tin oxide) films were grown by radio frequency (RF) magnetron sputtering and post thermal annealing. Both the thermal annealing temperature and the atmosphere significantly influenced the optical and electrical properties of ITO films. The as-grown 110-nm-thick ITO film showed an optical transmittance of 34.2% at a wavelength of 550 nm and electrical resistivity of 9.2×10-4 Ωcm. Notably, the ITO films annealed at 850 °C for 1 min in nitrogen ambient led to a significantly improved optical transmittance (97.3%) and the low electrical resistivity of 1.3×10-4 Ωcm, while those annealed in air or oxygen ambient produced poorer electrical properties despite their good optical transmittance owing to the presence of oxygen. The high quality of the ITO film annealed in nitrogen could be attributed to the combined effects of effective suppression of oxygen incorporation into films (thus maintaining oxygen vacancies in the ITO film), enhanced Sn doping, and improved the crystallinity with larger grain size.

A deep understanding of relationship between reverse time and growth of ITO film deposited by direct current pulsed sputtering

Indium tin oxide (ITO) film was deposited by the traditional direct current (DC) pulsed magnetron sputtering technology. With the increase of reverse time from 0 to 4.0 μs, the crystal structure of ITO film changed from the polycrystalline structure without preferred orientation to (1 0 0) preferred orientation. ITO film with (1 0 0) preferred orientation showed the satisfactory optical and electrical properties, such as the band gap in 4.15 eV and carrier concentration in 4.25 × 1020/cm3. Based on DC pulsed voltage waveform, the formation of (1 0 0) preferred orientation, as well as the change of optical and electrical properties of ITO film, were analyzed logically.

A simple route to prepare (100) preferred orientation indium tin oxide film onto polyimide substrate by direct current pulsed magnetron sputtering

The indium tin oxide (ITO) film was deposited onto the polyimide (PI) quartz, and Si (100) substrates by the traditional direct current (DC) pulsed magnetron sputtering technology, which no any heating treatment was carried out onto the substrates. With the increase of sputtering power density from 0.83 to 8.33 W/cm2, ITO films with different crystal structure, optical, and electrical properties were obtained. X-ray diffraction results showed that with the increase of sputtering power density, the crystal structure of ITO film changed from the polycrystal without preferred orientation to (100) preferred orientation. ITO film with (100) preferred orientation showed a satisfactory optical and electrical properties, which the band gap, resistivity, and carrier concentration was about 4.05 eV, 4.91 × 10−4 Ω cm, and 5.10 × 1020 cm−3, respectively. Combining the increase rate of ITO film growth rate, sputtering voltage, and sputtering current density, as well as DC pulsed voltage waveform, the formation of ITO film with (100) preferred orientation was analyzed logically. Finally, the relationship between sputtering power density and preferred orientation, as well as optical and electrical properties of ITO film, was investigated systematically. With above results, the short time overload sputtering voltage of DC pulsed sputtering process could be an ideal choice to prepare ITO film with (100) preferred orientation, especially for substrate without high temperature resistance.

Thickness Dependence of Properties of ITO Films Deposited on PET Substrates

Indium tin oxide (ITO) films with various thicknesses from 104 nm to 513 nm were prepared onto polyethylene terephthalate (PET) substrates by using r.f. magnetron sputtering without intentionally heating the substrates. The structural, optical, and electrical properties of ITO films were investigated as a function of film thickness. It was found that the amorphous nature of the ITO film was dominant below the thickness of about 200 nm but the degree of the crystallinity increased with an increasing thickness above the thickness of about 250 nm, resulting in the increase of carrier concentration and therefore reducing the electrical resistivity from 5.1 x 10(-3) to 9.4 x 10(-4) omega x cm. The average transmittance (400-800 nm) of the ITO deposited PET substrates decreased as the film thickness was increasing and was above 80% for the thickness below 315 nm. The results show that the improvement of the film crystallinity with the film thickness contributes to the increase of the carrier concentration and the enhancement of the electrical conductivity.

Indium Tin Oxide Film Characterization at 0.1–20 GHz Using Coaxial Probe Method

Indium tin oxide (ITO) is one of the most commonly used optically transparent conductors in applications, such as electro-optic antennas, displays, and optical coatings. However, their RF frequency-dependent electrical properties have not been reported in the literature. In this paper, we present measurements of the electrical properties (permittivity and conductivity) of ITO films in the 0.1-20-GHz frequency range. Measurements were carried out using an in-house open-ended coaxial probe technique employing a one-port reflection coefficient. As usual, calibration and numerical post-processing is needed to extract the electrical properties of the ITO film placed on a 0.5-mm-thick Eagle glass. The measured conductivity was on the order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> throughout the frequency range, and the real and imaginary parts of the permittivity were on the order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> at lower frequencies and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> at higher frequencies.

Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were-1.6E+20 cm−3,2.7E+01 cm2/Vs,1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.

Low temperature growth of ITO transparent conductive oxide layers in oxygen-free environment by RF magnetron sputtering

Indium Tin Oxide (ITO) thin films were grown at room temperature (RT) in oxygen-free environment by rf-magnetron sputtering on glass and Si(100)-substrates. The effects of argon pressure, sputtering power and film thickness on the electrical and optical properties of ITO films were investigated. For a 100 nm thick ITO films grown at RT in argon pressure 1.95·10−3 mbar and sputtering power of 50 W, the transmittance was near 90% at 480 nm and resistance was 5.4·10−4 Ohm·cm. It has been shown that the sputtering power plays an important role in electric properties of ITO films. SEM images of these samples show smooth surface with sharp substrate/ITO interface.

Indium Tin Oxide Films Grown at Room Temperature by RF-Magnetron Sputtering in Oxygen-Free Environment

Indium Tin Oxide (ITO) thin films were grown at room temperature (RT) in oxygen-free environment by rf-magnetron sputtering on glass and Si(100)-substrates. The effects of argon pressure, sputtering power and film thickness on the electrical and optical properties of ITO films were investigated. For a 100 nm thick ITO films grown at RT in argon pressure 1.95∙10-3 mbar and sputtering power of 50 W, the transmittance was near 90% at 500 nm and resistivity was 5.4∙10-4 Ohm∙cm. It has been shown that the sputtering power plays an important role in electric properties of ITO films. SEM images of these samples show smooth surface with sharp substrate/ITO interface.

Electrical and optical properties of ITO and ITO/Cr-doped ITO films

In this paper we report on the effects of the insertion of Cr atoms on the electrical and optical properties of indium tin oxide (ITO) films to be used as electrodes in spin-polarized light-emitting devices. ITO films and ITO(80 nm)/Cr-doped ITO(20 nm) bilayers and Cr-doped ITO films with a thickness of 20 nm were grown by pulsed ArF excimer laser deposition. The optical, structural, morphological and electrical properties of ITO films and ITO/Cr-doped structures were characterized by UV–Visible transmission and reflection spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Hall-effect analysis. For the different investigations, the samples were deposited on different substrates like silica and carbon coated Cu grids. ITO films with a thickness of 100 nm, a resistivity as low as ∼4×10−4 Ω cm, an energy gap of ∼4.3 eV and an atomic scale roughness were deposited at room temperature without any post-deposition process. The insertion of Cr into the ITO matrix in the upper 20 nm of the ITO matrix induced variations in the physical properties of the structure like an increase of average roughness (∼0.4–0.5 nm) and resistivity (up to ∼8×10−4 Ω cm). These variations were correlated to the microstructure of the Cr-doped ITO films with particular attention to the upper 20 nm.

Structural Properties of Post Annealed ITO Thin Films at Different Temperatures

Indium tin oxide (ITO) thin films were deposited on glass substrates by RF sputtering using an ITO ceramic target (In2O3-SnO2, 90-10 wt. %). After deposition, samples were annealed at different temperatures in vacuum furnace. The post vacuum annealing effects on the structural, optical and electrical properties of ITO films were investigated. Polycrystalline ITO films have been analyzed in wide optical spectrum, X-ray diffraction and four point probe methods. The results show that increasing the annealing temperature improves the crystallinity of the films. The resistivity of the deposited films is about 19×10 -4 Ωcm and falls down to 7.3×10 -5 Ωcm as the annealing temperature is increased to 500 °C in vacuum.

Correlation between diffraction patterns and surface morphology to the model of oxygen diffusion into ITO films

Indium tin oxide (ITO) films post-annealed in air usually have higher resistivity compared to the ITO films post-annealed in vacuum. This is likely due to the incorporation of oxygen atoms into the ITO films during post-annealing treatment in air. In this paper, we studied mainly the electrical properties of ITO films as a function of post-annealing temperature and post-annealing ambient. Our results show that the ITO films post-annealed in vacuum have lower resistivity compared to the ITO films post-annealed in air. From the results, we relate the model of oxygen diffusion with the AFM images and the (4 0 0)/(2 2 2) XRD peak ratio. We observe that the ITO films post-annealed in vacuum have larger grain size through the AFM images. The reduction of grain boundary scattering leads to higher conductivity. Furthermore, the ITO films post-annealed in vacuum have rather constant (4 0 0)/(2 2 2) XRD peak ratio. This result indicates that there is less oxygen atoms diffuse into the ITO films in vacuum. The ITO film post-annealed at 500 °C in vacuum has a grain size of ∼125 nm and resistivity of ∼3.49 × 10 −4 Ω cm.

Influence of Structural and Electrical Properties of ITO Films on Electrochromic Properties of WO&lt;sub&gt;3&lt;/sub&gt; Films

Indium tin oxide (ITO) films had been deposited on glass substrate without substrate heating and then tungsten oxide (WO3) films were deposited on ITO films by DC magnetron sputtering. In this work, we present the annealing ambient effect of ITO substrate on electrochromic properties of WO3 films. The ITO films were annealing in air and in vacuum at 350°C before coating with WO3 films. The structural, optical, and electrical properties of ITO films for as-deposited, annealing in air and in vacuum were investigated by X-ray diffraction, UV-VIS-NIR spectroscope and four point probe. The ITO films had a better crystallinity and lager grain size after annealing in air and in vacuum. The resistivity of ITO films increase with annealing in air, but decrease with annealing in vacuum. The WO3 films show difference surface morphology with higher grain size and surface roughness when coating on annealed ITO films in both cases. The electrochemical properties of film systems were characterized by cyclic voltammetry. The film systems of ITO plus WO3 showed that the charge capacity of ITO substrate annealing in vacuum was higher than the as-deposited ITO substrate and the ITO substrate annealing in air, respectively. This result corresponded to electrical conductivity of each ITO substrate.

Effect of annealing on the structural, optical and electrical properties of ITO films by RF sputtering under low vacuum level

Indium tin oxide (ITO) thin films were prepared by RF sputtering of ceramic ITO target in pure argon atmosphere at a high base pressure of 3×10−4mbar without substrate heating and oxygen admittance. The use of pure argon during deposition resulted in films with high transparency (80–85%) in the visible and IR wavelength region. The films were subsequently annealed in air in the temperature range 100–400°C. The annealed films show decreased transmittance in the IR region and decreased resistivity. The films were characterized by electron microscopy, spectrophotometry and XRD. The predominant orientation of the films is (222) instead of (400). The transmission and reflection spectra in the wavelength range 300–2500nm are used to study the optical behaviour of the films. The optical transmittance and reflectance spectra of the films were simultaneously simulated with different dielectric function models. The best fit of the spectrophotometric data was obtained using the frequency-dependent damping constant in the Drude model coupled with the Bruggeman effective medium theory for the surface roughness. It has been found that the sputtering power and the chamber residual pressure play a key role in the resulting optical properties. This paper presents the refractive index profile, the structure determined from the XRD and the electrical properties of ITO films. It has been found from the electrical measurement that films sputtered at 200W power and subsequently annealed at 400°C have a sheet resistance of 80Ω/□ and resistivity of 1.9×10−3Ωcm.