Doped Indium Oxide Thin Films Research Articles

Zirconium doped indium oxide thin films as transparent electrodes for photovoltaic applications

In this work we report on ultra-thin Zirconium doped In2O3 transparent conductive films grown at room temperature via RF-Magnetron co-sputtering. Samples from 15 nm to 90 nm thick, and low Zr atomic concentration (0.6–0.9 at.%), were annealed at T = 200 °C after the deposition. The phase-transition from amorphous to crystalline, confirmed by XRD measurements, leads to an improvement of both electrical and optical properties. The thinnest film (15 nm) shows electrical resistivity as low as 5 × 10−4 Ωcm, with carrier mobility of 20 cm2V−1s−1, and optical transmittance up to 80 % in visible and near-infrared range. IZrO electrode performances were tested through external quantum efficiency (EQE) measurements on a semi-finite Silicon Heterojunction bi-facial solar cell. The EQE values for 90 nm thick film are comparable to that of standard ITO when IZrO films are implemented as front electrodes. These results suggest that ultra-thin IZrO films may be successfully used to reduce costs and the amount of Indium used in Indium-based transparent conductive oxide layers for solar cells.

Molybdenum doped indium oxide thin films grown on mica substrates with high near-infrared transparency and electron mobility for flexible optoelectronic and spintronic applications

In the era of the artificial intelligence, flexible multifunctional films that combine optical transparency, electrical conductivity, and ferromagnetism are highly beneficial for many advanced applications. Herein, we fabricated a flexible magnetic transparent conductor molybdenum doped indium oxide (IMoO) thin film on a mica substrate using a pulsed laser deposition (PLD) technique. The valence states of Mo dopants were determined to be Mo4+ and Mo6+ by X-ray photoelectron spectroscopy (XPS) analysis. From the measured optical transmittance spectrum, average visible (Vis) and near-infrared (NIR) transmittance (Tave_Vis and Tave_NIR) values in IMoO film are calculated to be 85.9 % and 85.4 %, respectively. The IMoO film shows an electron mobility (μe) of around 113 cm2 V−1 s−1 and a sheet resistance (Rs) of 69 Ω. We illustrate the benefits of Mo doping, which leads to increased NIR transparency and μe compared to commercially available tin-doped indium oxide (ITO). On the other hand, the IMoO film shows clear magnetic hysteretic behaviors at room temperature, indicating the presence of ferromagnetism. The main origin of the ferromagnetism is presumably attributed to the Mo4+ ions with an electronic configuration of 4 d2. Bending cyclic tests reveal favourable mechanical durability and bending stability in the IMoO/mica films. Our systematic investigation demonstrates that IMoO film possesses a superior optoelectronic performance beyond ITO, Mn-doped indium oxide (IMnO), and Sn-Mn-codoped indium oxide (ITMnO), substantiating the potential of the IMoO/mica film as a high-performance transparent conductive magnetic material for flexible optoelectronic and spintronic applications.

The effect of thickness on the optical and electrical properties of Hf doped indium oxide thin films

The doping of Hf has great potential to adjust the optical and electrical properties of In2O3 films, which has rarely been reported. In this paper, Hf-doped indium oxide films (IHFO) with excellent optical (average transmittance: 95.81%) and electrical properties (resistivity: 7.1 × 10−4 Ω cm) were deposited by RF sputtering on the glass substrate. X-ray photoelectronic spectra (XPS) showed that Hf4+ substituted In3+, resulting in an increase in carrier concentration and thus decreased resistivity. The X-ray diffraction (XRD) and Scanning electron microscopy (SEM) indicated that the change in the preferred orientation of IHFO film from (400) to (222) leads to different shape grains, which are associated with nuclei merging due to thickness increase. As the optical path of the visible light in film increase with film thickness, the film's visible light absorption is enhanced, resulting in the average transmittance of the films decreasing from 95.81% to 87.68%. Considering the effect of thickness on optical and electrical properties, the IHFO film at a thickness of 893 nm exhibits the highest FOM value of 2.85 × 10−2 Ω−1 with high average transmittance (89.84%) and low sheet resistance(12 Ω/sq). This result indicates that the IHFO film deposited with optimal thickness can be an alternative for high-performance TCO in various optoelectronic fields.

Investigation on structural, optical and electrical properties of Zn doped indium oxide thin film for gamma dosimetry

Zinc-doped indium oxide thin film was deposited on the glass substrate using the spray pyrolysis method at a substrate temperature of 723K for various Zn concentrations in the range of 2–10 at%. The obtained film confirmed a polycrystalline cubic structure with a shift in preferred growth orientation from (400) to (222) on higher doping levels. The morphological study also exhibited a microstructure change which corroborates with the XRD spectra. Moreover, surface morphology has a great influence on the physical properties of the film. Cubic crystallization of doped In2O3 with no impurity phase and the presence of oxygen vacancies is confirmed by Raman spectra. It also confirms the In substitution by Zn. Optical transmittance decreased with doping which is supported by a decrease in bandgap energy from 3.68 to 3.5. The Refractive index is estimated using three different models with the Herve-Vandamme model showing the least deviation. Urbach energy shows an inverse relation with energy band gaps. Violet-blue emission was observed in the photoluminescence spectra. Zn doping also had an influence on the electrical properties of the material. Thermoluminescence spectroscopy validates Zn-doped In2O3 films' suitability for gamma dosimetry. XPS peak intensity corresponds to oxygen vacancies observed to be higher for Zn doped sample relative to undoped, indicates the formation of defects after doping. The resistivity increased up to 6 at% and then decreased, which can be due to the preferred orientation change to (222) at higher dopant concentrations. From the investigation, it is concluded that 4% Zn doped In2O3 can be used for sensor applications due to its good structural, optical and electrical properties and also lesser defects.

A novel reduction approach for fabrication of transparent conducting fluorine and tin doped indium oxide thin film with low sheet resistance

Surface and interface engineering of fluorine and tin doped indium oxide thin film at mild conditions to modulate optoelectronic properties is of great significance. Herein, a simple, low-cost solgel-spin-coating method was used to create a reproducible, scalable, stable, transparent, and conducting tin fluorine doped indium oxide thin film (FTIO thin film). To improve the electrical and optical properties of the thin film, a novel chemical reduction process was developed that did not require any reducing gas, inert atmosphere, and high temperature annealing. The chemical reduction time and concentration of NaBH4-dependent analysis shows a big drop (∼83%) in sheet resistance, due to increased oxygen vacancy in thin film. This increased oxygen vacancy was confirmed from XPS analysis. The treated FTIO thin film show lower resistivity (ρ = 0.95 × 10−3 Ω cm), highest figure of merit (0.001 Ω-1), roughness of 19.53 Å, and sheet resistance of 193 ± 3 Ω/sq, when compared to all other the solgel-spin-coating thin film process testified to date. To test the general applicability of the proposed reduction technique, it was applied to commercially available ITO thin film, and found to reduce sheet resistance by more than 53% (≤7 ± 1 Ω/sq) of the initial sheet resistance. Compared to other common post-treatment approaches, the proposed methodology reduces sheet resistance and could satisfy the demands of most real applications.

Effect of vacuum annealing on the optical and electrical properties of sputtered silicon doped indium oxide thin films

Silicon doped indium oxide (SIO) thin-films were deposited on Corning glass substrates using radio frequency magnetron sputtering at room temperature. The deposited SIO thin-films were post annealed under vacuum conditions (∼3.9 × 10−4 Pa) at 100–500 °C, respectively. The XRD analysis confirmed presence of polycrystalline indium oxide (In2O3) with preferred orientation in the (400) plane. Atomic force microscopy images show root mean square roughness ranging between ∼6 and 10 nm. The SIO thin-film post annealed at 400 °C had shown the electrical resistivity, mobility carrier concentration and sheet resistance values of 3.7 × 10−4 Ω-cm, 40 cm2/V.s, 4.2 × 1020 cm−3 and 4.96 Ω/□, respectively. The average transmittance of 76.2%, in the visible region (380–750 nm) was observed for SIO thin-film post annealed at 400 °C. The obtained results confirm that SIO thin films can be used for further development of high-performance transparent electrodes by sputtering technique.

Investigation of Electrical and Optical Properties of Low Resistivity Indium Oxide Thin Films

Indium Oxide (In2O3) is a wide bandgap (~3.6eV) n-type transparent conducting oxide (TCO) semiconductor with high conductivity and good transparency in the visible region [1]. In2O3 finds several applications such as photovoltaic devices, transparent windows in liquid crystal displays and heterojunction solar cells [2]. The electrical and optical properties of In2O3 films vary depending on the partial pressure of the reactive gas used for the specific deposition technique, target to substrate distance, temperature at which the substrate is exposed during heat treatment following deposition, and the ambience in which it is treated [3]. In2O3 films has been deposited using vacuum evaporation, sputtering [4], chemical vapor deposition [5], spray pyrolysis [6], ion assisted deposition [7], spin coating [8] and atomic layer epitaxial growth [9].In this work, In2O3 films are deposited on glass substrates by reactive sputtering of In2O3 target in presence of oxygen gas. The deposition was carried out under different flow rates of oxygen. The influence of oxygen gas flow on electrical and optical characteristics of the films are studied. Influence of oxygen gas flow on electrical resistivity of In2O3 thin films is investigated. Transmission characteristics of the deposited films are studied using UV-visible spectrophotometer. Absorption coefficient is calculated from the transmission values and optical bandgap is extracted from Tauc-plot. Min-Suk Lee, Won Chel Choi, Eun Kyu Kim, Chun Keun Kim, Suk-Ki Min, Characterization of the oxidized indium thin films with thermal oxidation, Thin Solid Films, Volume 279, Issues 1–2, 1996, Pages 1-3, ISSN 0040-6090.Abbas bagheri khatibani, Seyed Mohammad Rozati, Z. Bargbidi (2012). Preparation, Study and Nanoscale Growth of Indium Oxide Thin Films. Acta Physica Polonica Series a. 122. 220. 10.12693/APhysPolA.122.220.Radhouane Bel Hadj Tahar, Takayuki Ban, Yutaka Ohya, and Yasutaka Takahashi, Tin doped indium oxide thin films: Electrical properties, Journal of Applied Physics 83:5, 2631-2645.Sundaram, K.B. and Bhagavat, G.K. (1981), Preparation and properties of indium oxide films. phys. stat. sol. (a), 63: K15-K18.Cheng, G., Stern, E., Guthrie, S. et al. Indium oxide nanostructures. Appl. Phys. A 85, 233–240 (2006).Memarian, N., Rozati, S.M., Elamurugu, E. and Fortunato, E. (2010), Characterization of SnO2:F thin films deposited by an economic spray pyrolysis technique. Phys. Status Solidi (c), 7: 2277-2281.S. Cho, K. H. Yoon, S. K. Koh, J. Appl. Phys. 89, 3223 (2001).Gurto, M. Ivanovskaya, A. Pfau, U. Weimer, W. Gopel, Thin Solid Films 307, 288 (1997)Aikainen, M. Ritala, W. M. Li, R. Lappalainen, M. Leskele, Appl. Surf. Sci. 112, 231 (1997).

Jet nebuliser spray pyrolysed indium oxide and nickel doped indium oxide thin films for photodiode application

Indium oxide thin films at different substrate temperatures (250−450 °C) and nickel doped indium oxide films with various doping concentration of 10 and 15 wt% were coated (at 400 °C) using jet nebulizer spray pyrolysis technique confirmed the cubic phase of the films from X-ray diffraction analysis. The micro-strain effects were also verified by Williamson-Hall method. Field emission scanning electron microscopy (FE-SEM) confirmed temperature dependence in the formation of octahedron layered geometry. The influence of temperature on surface irregularity and its effect on band gap shift confirmed using optical characterization was attributed to Burstein-Moss shift. The influence on doping was reinforced with the emission peak shift of photoluminescence spectra in ultra violet, violet and blue regions (394, 421 and 467 nm). Based on confirmations from these characterizations, n-In2O3/p-Si junction diodes were fabricated for as prepared In2O3 and 10 and 15 wt% concentrations nickel doped In2O3 at 400 °C. P-N junction diodes fabricated and analyzed showed high sensitivity for 15 wt% nickel doped indium oxide under illumination condition. On account of this 15 wt% nickel doped junction diode is a good candidate for optoelectronic devices.

Solution processed boron doped indium oxide thin-film as channel layer in thin-film transistors

In this work, boron–indium-oxide (BIO) thin-film transistors (TFT) have been fabricated by a solution based processing method. We have studied the structural, morphological, optical and electrical properties of solution processed BIO thin-film for TFT applications. The dopant boron was chosen as an effective carrier suppressor in indium oxide thin-film, owing to high Lewis acid strength, electro-negativity, small ionic size and high boron-oxygen bonding strength. The boron concentration in the indium oxide precursor solution was varied from 0 to 50 at.%. X-ray diffraction analysis confirms the transition of polycrystalline indium oxide thin film to amorphous nature from boron concentration of 20 at.% and above. The thin-films had a uniform smooth surface with an average surface roughness between 0.10 and 0.17 nm. Moreover, the thin-films were shown to be highly transparent (> 86%) in the visible region. The synthesized BIO thin-film was patterned and used as the active channel layer for TFT devices that were fabricated. The BIO (25 at.% boron) TFT post-annealed at 350 °C exhibited amorphous nature with a field effect mobility of 0.8 cm2/V s with threshold voltage at 6.8 V and ION/IOFF of about 4.5 × 108.

Effect of gamma-irradiation on optical, structural and electrical properties of In2O3: F thin films for photocatalysis application

Fluorine-doped indium oxide thin films (In2O3: F) have been successfully synthesized by spray pyrolysis technique on glass substrates and irradiated by different doses (1, 5, 10 and 100 kGy) of gamma-radiations using Co60 gamma source. The effect of this high energy on physical properties of In2O3: F has been studied by X-Ray diffraction, Raman spectroscopy, Spectrophotometer, Photoluminescence spectrometer and Hall Effect measurements. In our study γ-radiation induces an enhancement on the physical properties of fluorine doped indium oxide thin films. Especially at 10 kGy, optical transmission and electrical resistivity were improved after irradiation so the transparent conductor character has been improved also. In2O3: F thin film crystallized into the cubic structure with predominant plan orientation (4 0 0) located at 2θ = 35.46°. An increase of transmission values from 77 to 83% is detected after irradiation. The optical band gap increases from 3.01 eV to 3.18 eV. The effect of gamma radiation on optical constants such as refractive index n (λ), extinction coefficient k (λ), lattice dielectric constant εL, high frequency dielectric constant ε∞, plasma frequency ωP have been determined. The Wemple model based on the envelope method were applied to calculate the single oscillator energy E0 and dispersion energy Ed. A decrease of electrical resistivity from 0.43 to 0.14 Ω cm is also detected after irradiation. All these experimental results suggest that In2O3: F thin films can be used as transparent conductive electrode in photovoltaic devices. This study also illustrates that In2O3: F thin film irradiated at 100 kGy can be used as a photocatalytic material with an efficiency to decompose the dye around 84%.

Improvement of structural, optical and electrical properties of iron doped indium oxide thin films by high gamma radiations for photocatalysis applications

Iron doped indium oxide (In2O3:Fe) thin films have been deposited on glass substrates by spray pyrolysis technique and irradiated by four high gamma doses 1, 5, 10 and 100 kGy. We have investigated the influence of applied gamma radiations on structural, optical, photoluminescence and electrical properties of In2O3:Fe thin films using X-ray diffraction, Raman spectroscopy, spectrophotometer, Photoluminescence spectrometer and Hall Effect measurements. Structural analysis revealed that preferred orientation (400) plan depicted at 2θ = 35.5° was kept after exposure to gamma radiations with a noticeable improvement of crystallinity for all doses. Average transmission values in the transparent domain [600–2500] nm were increased from 79% to a maximum value of 88% for irradiated thin layer by 10 kGy. Band gap energy was also increased from 3.32 eV to 3.5 eV after irradiation by 10 kGy. Different optical parameters such as refractive index n(λ), extinction coefficient K(λ), lattice dielectric constant (εL), high frequency dielectric constant (ε∞), plasma frequency (ωP) and the ratio of carrier concentration to electron effective mass (Nm*) were determined and analyzed. Single-oscillator Wemple-Didomenico model was applied to calculate the dispersion parameters E0 and Ed after gamma irradiation. Photoluminescence spectra of thin films show an overall decrease in their peak intensities after γ-irradiation. Hall Effect measurements of In2O3:Fe thin films revealed that electrical resistivity have been decreased from 5.07 * 10−2 Ω cm to a minimum value of 1.75 * 10−2 Ω cm at 10 kGy. All these good experimental results can lead to a potential use of gamma irradiated iron doped indium oxide thin film for optoelectronic devices. Photocatalytic activity of γ-irradiated In2O3:Fe thin films to decompose methylene blue were studied under sun light. Optimum irradiated thin film shows an enhancement of photocatalytic activity under sun light with a percentage of dye decolorization equals to 87%.

Performance improvements of tungsten and zinc doped indium oxide thin film transistor by fluorine based double plasma treatment with a high-K gate dielectric

The electrical characteristics and XPS analysis for the amorphous tungsten and zinc doped indium oxide thin film transistor, which was performed with single or double different fluorine based remote plasma treatment, were investigated in this study. A high mobility TFT device with the tungsten doped channel was fabricated in the previous study, but there was an inevitable negative shift for the threshold voltage, which will be a limit for the application of systemic circuit design. Therefore, a double fluorine based remote plasma treatment process is proposed for the high electronegativity of fluorine element and its similar radius as oxygen, which can be used to terminate the donor-like oxygen vacancy. It may induce a positive shift of threshold voltage, while carrier concentration and field effect mobility might be maintained. As a result, the sample with CF4/N2 + O2 plasma treatment exhibits a higher on/off current ratio of ~4.73 × 106, a lower sub-threshold swing value of 0.070 V/decade, and a lower interfacial trap density value of 5.21 × 1011 eV−1 cm−2 than other samples, while there is even a desirable positive shift of threshold voltage and acceptable field effect mobility of 31.2 cm2/Vs. This research proposes an effective approach to improve the reliability characteristic and adjust the inevitable negative shift of threshold voltage without sacrificing the carrier mobility of device.

Understanding near infrared absorption in tin doped indium oxide thin films

Tin doped indium oxide (In2O3:Sn (ITO)) thin films RF sputtered under similar conditions on soda lime glass and single crystal silicon wafers (c-Si) are used to study near infrared optical absorption variations during film growth. The presence of strong free carrier absorption and phonon absorption in the low photon energy spectral range provides an opportunity to disentangle tailing effects extending in the near infrared to visible spectral range. Toward that end, a model describing ITO film optical properties in the form of the complex dielectric function (ε = ε1 + iε2) from ex situ ellipsometry collected over 0.4 to 4.1 meV, 0.035 to 0.4 eV, and 0.75 to 5.89 eV spectral range is developed to describe these features along with other higher energy electronic transitions. In situ real time spectroscopic ellipsometry (RTSE) from 0.75 to 5.89 eV is used to track changes film structure and optical response during thin film growth. Optical emission spectroscopy indicates the plasma is very stable during deposition implying that film property changes with thickness are not correlated with changes in plasma chemistry. Film resistivity (ρ), mobility (µ), scattering time (τ), and carrier concentration (n) are determined from the free carrier absorption component of ε. Increased near infrared absorption manifested in ε obtained from RTSE data analysis is hypothesized to originate from enhancement of OH-group phonon absorption due to the presence of water molecules in the chamber at the beginning of growth.

Oxygen vacancy induced room temperature ferromagnetism in (In1−xNix)2O3 thin films

Nickel doped indium oxide thin films (In1−xNix)2O3 at x = 0.00, 0.03, 0.05 and 0.07 were deposited onto glass substrates by electron beam evaporation technique. The deposited thin films were subjected to annealing in air at 250 °C, 350 °C and 450 °C for 2 h using high temperature furnace. A set of films were vacuum annealed at 450 °C to study the role of oxygen on magnetic properties of the (In1−xNix)2O3 thin films. The thin films were subjected to different characterization techniques to study their structural, chemical, surface, optical and magnetic properties. All the synthesized air annealed and vacuum annealed films exhibit body centered cubic structure without any secondary phases. No significant change in the diffraction peak position, either to lower or higher diffraction angles has been observed. The band gap of the films decreased from 3.73 eV to 3.63 eV with increase of annealing temperature from 250 °C to 450 °C, in the presence of air. From a slight decrease in strength of magnetization to a complete disappearance of hysteresis loop has been observed in pure In2O3 thin films with increasing the annealing temperature from 250 °C to 450 °C, in the presence of air. The (In1−xNix)2O3 thin films annealed under vacuum follow a trend of enhancement in the strength of magnetization to increase in temperature from 250 °C to 450 °C. The hysteresis loop does not disappear at 450 °C in (In1−xNix)2O3 thin films, as observed in the case of pure In2O3 thin films.

Effects of V doping on magnetic and optical properties of oxygen-deficient In2O3 thin films

The scope of the work was to study structural, optical and magnetic behaviors of vanadium (V) doped indium oxide thin films prepared by thermal evaporation. Thin films of vanadium doped oxygen deficient In2O3 were deposited on sapphire, corning glass and Si(100) substrates. EDAX analysis revealed a great reduction in oxygen was happen during evaporation and oxygen deficient undoped and V doped In2O3 thin films were formed. XRD characterization suggested that the present In2O3 portion was in the amorphous state and the observed crystalline peaks were indexed as tetragonal metallic indium. The undoped In2O3 had the lowest transmittance and the transmittance increased with increasing V doping. The optical band gap and refractive index values decreased with increasing V doping. The dependence of magnetization on magnetic field for V doped In2O3 thin films were studied at 300K and 5K. All the samples exhibited soft ferromagnetic behaviour. The parameters of the hysteresis loop were extracted. The achieved results may find usage in magneto-optical applications.

Correlation between structural and optoelectronic properties of tin doped indium oxide thin films

Spin coating method was employed to deposit the thin films using redispersed nanoparticle suspensions of tin doped indium oxide (ITO). These films were then annealed in air at 450, 500, 550, 600, and 650°C for 1h. The effect of annealing temperature on the structural, optical, morphological, and electrical properties were studied by XRD, UV–vis spectroscopy, SEM, and four point probe technique, respectively. XRD analysis revealed that all thin films have cubic bixbyite structure with dominant (2 2 2) plane. Williamson-Hall analysis of XRD patterns showed that crystallite size increases with the rise in annealing temperature. SEM images of ITO thin film depicted spherical and non-spherical shaped particles of uneven size. The transmission spectra obtained from UV–vis spectroscopy reveals that transparency of thin films undulate with annealing temperature. With the rise in annealing temperature the optical band gap increases, while the Urbach energy and electrical resistivity decreases. The optical band gap, Urbach energy, and electrical resistivity were found to have systematic dependence on the crystallite size. The figure of merit is maximum for ITO thin film annealed at 550°C.

Study on the physical properties of europium doped indium oxide thin films

Structural, morphological, optical and electrical properties of europium doped In2O3 thin films grown by spray pyrolysis technique are studied in this work. The atomic percentages of europium dopant in In2O3-based solution were y = ([Eu3+][In3+])sol=0; 0.1; 0.3 and 0.5at%. All films crystallize into the body centered cubic structure. The preferred orientation peak along the (222) plane was changed to (400) after doping. It is further revealed a best crystallinity for y =0.3at% followed by a noticeable increase of the grain size. Some structural and microstructural parameters are determined using Rietveld refinement of XRD patterns. The optical transmission of doped films was above 68% in the visible range. The optical band gap (Eg) is in the range of [3.43–3.51]eV. Optical constant such as refractive index (n), packing density (p), porosity, oscillator energy (E0) and dispersive energy (Ed) were also studied in this report using envelope method based on transmission-reflection spectra. Electrical properties show a lowest resistivity (ρ) for a doping concentration equals to 0.3at% reaching 0.031Ωcm. At this doping ratio, an enhancement of free carrier concentration is also remarked. A heat treatment under nitrogen atmosphere is then applied on optimized In2O3:Eu (0.3at%). A significant decrease of the resistivity is noted at 250°C during 2h reaching 0.004Ωcm. These results lead to conclude that annealed In2O3:Eu(0.3at%) can be a good candidate to be used in many optoelectronic devices and especially as optical window or transparent electrode in solar cells.

The physical properties of nickel doped indium oxide thin film prepared by the sol-gel method and its potential as a humidity sensor

Ni doped In2O3 (NixIn2−xO3: x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10) films have been successfully prepared by a sol-gel method. All films have nanograins, cubic structures and single phase. The Ni unsystematically affected the film thickness and surface roughness. All films showed high transmission percentage i.e. in the range of 92–99% at wavelength more than 380 nm. All films except film with x=0.02 and 0.06 have magnetic properties. It is also found that all of the films were sensitive towards the humidity changes and can be used as a humidity sensor.

Electronic structure of transparent conducting Mo-doped indium oxide films grown by polymer assisted solution process

Transparent conducting properties of molybdenum doped indium oxide thin films by polymer-assisted solution (PAS) were investigated as a function of Mo doping concentration. Indium oxide films with molybdenum of ~1.5% (MIO) showed lowest electrical resistivity with 7.89×10−4 Ω cm, compared to those of indium oxide films with 4.39×10−3 Ω cm. The enhancement of the transparent conducting properties by molybdenum doping were explained by the electronic structure in terms of chemical bonding states, band edge states below the conduction band, and band alignment. Molybdenum doping into indium oxide films resulted in the evolution of the conduction band and the change of band alignment.

Influence of Oxygen Partial Pressure on Opto-Electrical Properties, Crystallite Size and Dislocation Density of Sn Doped In $$_2$$ 2 O $$_3$$ 3 Nanostructures

In this research, high-quality Sn doped indium oxide (ITO) thin films were grown on glass slide substrates using an electron beam evaporation method. Vacuum chamber partial pressure was changed and the electro-optical as well as the microstructure parameters were investigated. The microstructure of prepared films was evaluated by x-ray diffraction analysis in terms of crystallite size and dislocation density. It was found that the best results [high transparency (88%) over the visible wavelength region, low sheet resistance of 12.8 \(\Omega \)/square, the optical band gap of 3.76 eV, crystallite size of 49.5 nm and dislocation density of \( 1.42 \times \,10^{14}\) m\(^{-2}\)] were achieved for the sample produced at a partial pressure of \( 1 \times \,10^{-4}\) mbar. Therefore, one can successfully control the physical properties of ITO films by varying the oxygen content of the evaporation system. The correlation between the band gap and carrier concentration in addition to the average crystallite size of films was also established.